I found these optical yellows on Amazon:
https://www.amazon.com/Gateron-Optical-switches-Switches-Keyboard/dp/B093GHLYSR?th=1As for cutting off the metal legs, do not do that, normal mechanical switches have leaf's where opticals don't and the leaf is what sends the signal to the pins, without the legs the mechanical switch will not work with an optical PCB, or mechanical PCB.
Some good beginner keyboards in my book are:
TES68, a nice 15$ tray mount 65% kit that's easily moddable and has hotswap sockets. you can burger mount it if you want a bit more out of it but it's nothing special.
The MK870 is basically just the TKL version of the TES68, comes at around 80$, and has south facing RGB with hotswap sockets but is tray mounted.
MW65, a more premium 80$ stacked acrylic gasket mount 65% kit that is very good for modding and fun to build and has south facing RGB and hotswap sockets. Has a more middle-ground sound and is a good experience for building but may not be as good as the Bakeneko.
The Bakeneko, an amazing 120$ aluminum keyboard option that utilizes the same mounting method as the famous Unikorn keyboards and has a really nice feel and sound to it (hotswap with south facing sockets) and is also in-stock with a 60% and 65% option. Does great with PE foam and higher pitched builds
whatever one of these you pick will be great but the Bakeneko is a great experience so if you can afford it I would highly recommend it
also one night i typed out an absolute chonker of a essay about QK65 but a lot of the stuff transfers over to this soo.....
https://geekhack.org/index.php?topic=116537.msg3122135#msg3122135