Indeed, HTML5 support was removed from UE at around 4.24, and today you have the two alternatives you mentioned for picking:
UE’s official option, Pixel Streaming, where the game runs on a server with a GPU, and the browser only receives a video stream, while sending input back. Main advantage is that a game can run in almost any machine, as the work is not being done on it, but you need to deal with latency, and having enough GPU instances in your server for each player
The alternative WebGPU solutions, which compile the project to run directly in the browser, so the player’s own hardware does the work, and there’s no need for servers. Performance will vary between players, and some UE features won’t work as intended, or at all
Now, since you want to keep loads and reqs in a reasonable level, Pixel Streaming would be the most reliable option, as long as your number of concurrent players is low.
On the other hand, if you expect a high ammount of players at the same time, a WebGPU method makes more sense, but it will demand further planning, specially on keeping your project as light as possible (small textures, simple materials, no use of Lumen or Nanite, etc).