There are options on Amazon for replacing. Please share any experience with non-UHK replacement key switches. Thanks!
Well, there are hundreds of options, and at the end of the day, experience depends on personal taste ¯\(ツ)/¯.
As far as I can tell, above silent red / pink sound as an excelent choice given your requirements.
Personally, when it comes to tactiles, I like switches with no pre-travel, and short travel distance. I am now using tecsees medium tactile, and although it took some time to get used to them, I am happy with them now. (They are pretty loud though.) I am also quite happy with kailh copper speed switches. (They are pretty loud too.)
I don’t mind linears, and am thinking of using them for a silent keyboard sometime in the future.
I am also keen to try out some of the low-profile options on the switch keys
Low profile switches are not compatible with UHK due to different pin layout.
There are some compatible medium-profile switches, but as far as I know, nothing silent. See The "low profile" UHK - #13 by Zetaphor .
I also read about people lubricating their switches to make them less “hard”. Is that a real thing ?
Yes, although I have no experience with that…
How does one go about doing that with the UHK v2 ? Thanks
Just as with any other mechanical keyboard I guess. Take the switches out, disassemble them, lubricate them, put them back together and back in your keyboard.
This is not UHK specific, so you are likely to find relevant information on general mech keyboard forums, reddit, youtube.