Tested the snap package and it works fine!
Running on DELL XPS13
Version 84.0.4147.89 (Official Build) snap (64-bit)
+ using the h264ify extension in the browser to force Youtube (VP9 by default) to run on h264


$ sudo snap install --channel=candidate/vaapi chromium

$ cat /etc/lsb-release 
DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=20.04
DISTRIB_CODENAME=focal
DISTRIB_DESCRIPTION="Ubuntu 20.04.1 LTS"

$ vainfo
libva info: VA-API version 1.7.0
libva info: Trying to open /usr/lib/x86_64-linux-gnu/dri/iHD_drv_video.so
libva info: Found init function __vaDriverInit_1_7
libva info: va_openDriver() returns 0
vainfo: VA-API version: 1.7 (libva 2.6.0)
vainfo: Driver version: Intel iHD driver for Intel(R) Gen Graphics - 20.1.1 ()
vainfo: Supported profile and entrypoints
      VAProfileMPEG2Simple            :	VAEntrypointVLD
      VAProfileMPEG2Main              :	VAEntrypointVLD
      VAProfileH264Main               :	VAEntrypointVLD
      VAProfileH264Main               :	VAEntrypointEncSliceLP
      VAProfileH264High               :	VAEntrypointVLD
      VAProfileH264High               :	VAEntrypointEncSliceLP
      VAProfileJPEGBaseline           :	VAEntrypointVLD
      VAProfileJPEGBaseline           :	VAEntrypointEncPicture
      VAProfileH264ConstrainedBaseline:	VAEntrypointVLD
      VAProfileH264ConstrainedBaseline:	VAEntrypointEncSliceLP
      VAProfileVP8Version0_3          :	VAEntrypointVLD
      VAProfileHEVCMain               :	VAEntrypointVLD
      VAProfileHEVCMain10             :	VAEntrypointVLD
      VAProfileVP9Profile0            :	VAEntrypointVLD
      VAProfileVP9Profile2            :	VAEntrypointVLD


chrome://media-internals/

Timestamp	Property	Value
00:00:00.000	origin_url	"https://www.youtube.com/"
00:00:00.000	kFrameUrl	"https://www.youtube.com/watch?v=LXb3EKWsInQ"
00:00:00.000	kFrameTitle	"COSTA RICA IN 4K 60fps HDR (ULTRA HD) - YouTube"
00:00:00.000	url	"blob:https://www.youtube.com/bd1489d5-5381-4f8a-b3c0-90023da92ae9"
00:00:00.000	info	"ChunkDemuxer"
00:00:00.000	pipeline_state	"kStarting"
00:00:00.036	kVideoTracks	[{"alpha mode":"is_opaque","codec":"h264","coded size":"1920x1080","color space":"{primaries:BT709, transfer:BT709, matrix:BT709, range:LIMITED}","encryption scheme":"Unencrypted","has extra data":false,"hdr metadata":"unset","natural size":"1920x1080","orientation":"0°","profile":"h264 high","visible rect":"0,0 1920x1080"}]
00:00:00.036	kAudioTracks	[{"bytes per channel":2,"bytes per frame":4,"channel layout":"STEREO","channels":2,"codec":"aac","codec delay":0,"discard decoder delay":false,"encryption scheme":"Unencrypted","has extra data":false,"profile":"unknown","sample format":"Signed 16-bit","samples per second":44100,"seek preroll":"0us"}]
00:00:00.039	info	"Effective playback rate changed from 0 to 1"
00:00:00.039	event	"kPlay"
00:00:00.045	kIsAudioDecryptingDemuxerStream	false
00:00:00.045	kAudioDecoderName	"FFmpegAudioDecoder"
00:00:00.045	kIsPlatformAudioDecoder	false
00:00:00.045	info	"Selected FFmpegAudioDecoder for audio decoding, config: codec: aac, profile: unknown, bytes_per_channel: 2, channel_layout: STEREO, channels: 2, samples_per_second: 44100, sample_format: Signed 16-bit, bytes_per_frame: 4, seek_preroll: 0us, codec_delay: 0, has extra data: false, encryption scheme: Unencrypted, discard decoder delay: false"
00:00:00.046	error	"{\"causes\":[{\"causes\":[],\"data\":{},\"stack\":[{\"file\":\"../../media/filters/decrypting_video_decoder.cc\",\"line\":53}],\"status_code\":264,\"status_message\":\"\"}],\"data\":{\"Decoder name\":\"DecryptingVideoDecoder\"},\"stack\":[{\"file\":\"../../media/filters/decoder_selector.cc\",\"line\":172}],\"status_code\":265,\"status_message\":\"\"}"
00:00:00.065	kIsVideoDecryptingDemuxerStream	false
00:00:00.065	kVideoDecoderName	"MojoVideoDecoder"
00:00:00.065	kIsPlatformVideoDecoder	true
00:00:00.065	info	"Selected MojoVideoDecoder for video decoding, config: codec: h264, profile: h264 high, level: not available, alpha_mode: is_opaque, coded size: [1920,1080], visible rect: [0,0,1920,1080], natural size: [1920,1080], has extra data: false, encryption scheme: Unencrypted, rotation: 0°, flipped: 0, color space: {primaries:BT709, transfer:BT709, matrix:BT709, range:LIMITED}"
00:00:00.065	pipeline_state	"kPlaying"
(...)

$ lspci
00:00.0 Host bridge: Intel Corporation Xeon E3-1200 v6/7th Gen Core Processor Host Bridge/DRAM Registers (rev 08)
00:02.0 VGA compatible controller: Intel Corporation UHD Graphics 620 (rev 07)
00:04.0 Signal processing controller: Intel Corporation Xeon E3-1200 v5/E3-1500 v5/6th Gen Core Processor Thermal Subsystem (rev 08)
00:14.0 USB controller: Intel Corporation Sunrise Point-LP USB 3.0 xHCI Controller (rev 21)
00:14.2 Signal processing controller: Intel Corporation Sunrise Point-LP Thermal subsystem (rev 21)
00:15.0 Signal processing controller: Intel Corporation Sunrise Point-LP Serial IO I2C Controller #0 (rev 21)
00:15.1 Signal processing controller: Intel Corporation Sunrise Point-LP Serial IO I2C Controller #1 (rev 21)
00:16.0 Communication controller: Intel Corporation Sunrise Point-LP CSME HECI #1 (rev 21)
00:1c.0 PCI bridge: Intel Corporation Sunrise Point-LP PCI Express Root Port #1 (rev f1)
00:1c.2 PCI bridge: Intel Corporation Sunrise Point-LP PCI Express Root Port #3 (rev f1)
00:1c.4 PCI bridge: Intel Corporation Sunrise Point-LP PCI Express Root Port #5 (rev f1)
00:1d.0 PCI bridge: Intel Corporation Sunrise Point-LP PCI Express Root Port #9 (rev f1)
00:1f.0 ISA bridge: Intel Corporation Sunrise Point LPC Controller/eSPI Controller (rev 21)
00:1f.2 Memory controller: Intel Corporation Sunrise Point-LP PMC (rev 21)
00:1f.3 Audio device: Intel Corporation Sunrise Point-LP HD Audio (rev 21)