What's your current level of handiness? Because that heavily influences your decision as to what you can handle vs what you hire out.
I consider myself pretty handy, but cautious. I make things in a community woodshop pretty frequently and don't mind getting into crawlspaces. But having only rented, I have limited home repair experience - just basic stuff like hardware replacements and re-caulking. I did rip out tile and lay a new LVP floor for my parents last year. But no experience with the real guts of a home.
Ok. Then, here's my thoughts.
Roof - if you are comfortable with heights and have someone who can buddy you (do not do this alone), maybe. It depends on what is the problem, where it is, and do you think you can fix it after watching a bunch of videos about roofing.
Furnace - I wouldn't start your plumbing career on gas lines. However, it also depends on exactly what is required to fix this. Watch some youtube videos and evaluate.
Gutters - again, depends on your ability to work on a ladder, how high it is, etc. If you attempt it, make sure you have someone else there to assist/spot you. And if you do it, make sure you clean out all the gutters and downspouts.
Kitchen sink - I would first check if there is a valve but it doesn't have a handle. That is easy to fix, all you need to do is screw on the handle. If you actually don't have a shut off, ie to turn off the water you have to turn off all the water, that is a lot more complicated. This isn't an emergency item, so it could wait until you get a bit more experience to decide if you're calling the plumber or not.
Siding - You'd need at least one other person, and it's a bigger job. Get some experience with house repairs, watch some videos, and then evaluate.
Windows Replace rotted window sills on second floor - for small areas of rot, you can repair it with wood hardener and wood filler. If it's beyond that, it sounds like you have the skill to fabricate. The height will complicate things. Don't bother with cedar, just fix the gutter problem and keep the exterior in good repair.
Porch Replace - Go for it, but also make sure you've addressed the underlying cause (assuming it's not the gutter).
Crawlspace Replace - DIYable, not fun, and wear PPE. You don't want to breath in the junk.
Kitchen sink - yep, DIY. My experience is just replace.
A/C Install a damper to improve upstairs cooling - Be careful you don't mess up overall hvac. You can install the damper, but messing with ducts can cause other issues. Recommend posting that project here to get some input if its a good idea.
Replace and/or balance some of the ceiling fans - yep. 2nd person is helpful.
Fasten two loose pedestal sinks - yep.
Replace light bulbs (lol) - you'd be surprised, depending on location it's really hard to get to them.
Replace drain stopper - assuming tub. Either easy, or surprisingly complicated.
Patch chips in bathtub - yep
Add insulation to some of the ducts in the attic - careful not to fall through the floor
Clean dirty HVAC ducts and change the dirty filters - you can do a lot, but without a compressor/long enough hoses you can't get it all. Do what you can and evaluate from there. Careful not to blow it all into the furnace. Wash the covers while you have them off too.
Overall, your ability to be safe and work effectively at heights is a major determining factor. Do NOT force the issue. If you can't, you can't.
