I looked at brief descriptions of quite a few L2 projects. Isn't there at least one or more which do not use new tokens, they are a "true layer on top" which helps give Bitcoin more powerful smart contracts?
The only "true layer on top", sufficiently developed and actively researched and maintained is Lightning. Everything else is just another blockchain.
In addition, most of those layer 2 are highly centralized[1] or doesn't even require Bitcoin blockchain to remain operational[2].