Agreed - I made the mistake of using a small CSS starter framework and regretted it a few weeks into the project. CSS size isn't usually a problem for anything I do (internal backends typically) so I tend to just put bootstrap in and go.
I think things like this (Shoelace) are a great learning experience for the developer(s) in question or for fun throwaway stuff. You could make an argument for them for a team project where there's wide agreement, but for anything I will need to maintain or share with someone or hand off I pretty much only use Bootstrap as a starting point. Saves a lot of headaches down the line.
I am IMO; V4 might be a total rewrite but there's still some commonality between it and V1 with class names & concepts. I wasn't suggesting that current bootstrap and v1 are the same thing. For anything that I would need to support or work with others on, using a well-established CSS framework like Bootstrap (v-whatever) has always been safer and more productive in the long run. YMMV.
I think things like this (Shoelace) are a great learning experience for the developer(s) in question or for fun throwaway stuff. You could make an argument for them for a team project where there's wide agreement, but for anything I will need to maintain or share with someone or hand off I pretty much only use Bootstrap as a starting point. Saves a lot of headaches down the line.