Injured/arthritic knees... how to work around????

[Elleon]

I've been having some issues with my knees over the past few months and i suspect it is something to do with my cartilage.
I have lightened my load on leg day as i don't want to aggravate it further.
i feel a stiffness in the knees every time i try to bend down.
i am avoiding squats and lunges as my knees begin to hurt as soon as i get to parallel on squats.
i am currently doing hack squats, leg extensions and leg presses because they don't hurt my knees.
however i feel i am limited by only doing these exercises.

I am scared of losing the muscle i currently have in my legs if i take some time off training, however if that is the only thing i can do then i'll have to do it.
do you have any suggestions for me in terms of exercises or keeping them active to reduce muscle loss if i take a break?

Any advice is greatly appreciated!
Thanks!

[Elleon]

bump

[riseboi]

Based on what you've written, I'd be suspicious of weakness in your hamstrings. If available, I'd recommend getting some sort of professional to visually evaluate you while you do these painful movements and to assess your hips.

[akfit16]

Are you having any crepitus (grinding/crackling) through any movements, even with just simple walking? The last time you ran did you feel like you had pain when flexing and extending the knee? Does it feel like it is on the anterior or posterior? If it feels like it is underneath the patella it could be patellofemoral pain syndrome/runner's knee. You don't have to run to injure it though.