Updating a late 2015 iMac with fusion drive

My iMac is Retina 4K, 21.5-inch, Late 2015 with Fusion drive (2TB HD and 128 SSD) setup as one drive.It says is model 16.2 with 3.1 GHz Quad-Core Intel Core i5. The model identifier is iMac 16.2.

I can not update beyond macOS Monterey. I understand Apple stopped updating the security on this. I am thinking of updating it to Sequoia using Open Car Legacy Patcher. My questions are

1. Can I do that on this machine?
2. If I can, Who o follow for simple undebatable step by step instructions.
3. If I succeeded in installing, How can I deal with future macOS updates? Do I have to start from beginning again?
4. I have tried to go through several updates and I get concussed quickly. Can anyone to help and explain it to a non-geek person?

Thank you