Oh, hello there!
First of all, thank you so much for your comment!
The biggest issue I had during the development was lighting. If you use default scenes like “first person template” and “ship” this level as a HTML5 game all will be good and fine. BUT, if you touch the default lighting setting or your level goes bigger there you can get some problems after exporting your game. I had to export and reupload the game about 40 times trying different lighting settings. And the best solution I found is to use Point Lights to light up my scene, because Sunlight did not work properly for some reason.
I can recommend using UE4.22 for HTML5 games only if :
1) you have some knowledge about Lighting setup (I definitely will create a test level with rooms and point lights for a science)
2) your game included really “light” assets, because UE build is heavy and barely fit in Itch.io.
P.S. There are probably some export settings and limitations for HTML5 that I don't know about, this was my first time making a game for a browser.