[Solved] Having trouble with Jekyll on a new laptop: Help a casual web dev dum-dum out!

Since I moved to a new laptop, my Jekyll setup seems to have become unusable. It appears the gems required by my site aren't found, or properly configured, even after a bundle install command that updated a bunch of them.

~~Error messages on bundle exec jekyll serve: https://pastebin.com/gyg8YpMx~~

Result of bundle install: https://pastebin.com/LKSstmJt

I'm by no means a Jekyll or Ruby expert (barely a user), but I used to have a tolerably functional environment to update my site. Any help on getting that up and running again is much appreciated!

Update 1:

I managed to solve the SASS issue that @Kissaki@programming.dev pointed out. Now the bundler asks about a possible typo in a gallery plugin 😰

See new error messages on bundle exec jekyll serve: https://pastebin.com/kk6HHv7Y I hope not every line in there is an error I have to fix...

Update 2 (solved)

Edited the RB plugin file according to the error message, and ...that was all? The site generates as in the olden days.

Thank you all who chipped in with advice!