OP already pointed that out and mentioned sidechains and/or layer 2 solutions.
If the lightning network will be supported, it will really be good, but will the lightning network be used with bitcoin DeFi tokens for making transactions also? This will really be nice because I can also help in lightning network adoption. But the issue if scaling solution is still the talk about bitcoin. If DeFi is introduced into bitcoin, that means more people will make bitcoin transaction when their is not effective scaling solution unlike the BSC except the lightning network. If people will make use of the bitcoin lightning network effectively, it will be a good solution.