Need some help with an overheating acer nitro 5

Hiiii! So, this old boy of mine started overheating to the point of the system rebooting. After doing some optimization (as shared on that guide that's highlighted on this subreddit), the temps are still running pretty high. As much as I'm tempted to just buy a proper laptop cooling fan and be done with it, I also know that I'm long overdue for both fan cleaning and thermal repasting (buddy has existed for almost five years now and has never tasted any fresh paste). I found some videos on youtube about how to do those thing but now I'm a bit stuck on some parts. I would really appreciate it anyone who has experience with replacing their old thermal pads and paste can answer some of my questions.

1. Is it better to just let a computer repair shop handle the maintenance of my laptop or is it better if I just do it myself? Time and whatnot isn't really an issue but money kind of is. I'm a bit tight on money recently but I need my laptop even more since I'm also using it for my thesis.

2. If I do push through with doing the maintenance on my own, what tools do I need to buy?

3. What does the Acer Nitro 5 use? Thermal putty, paste or pads? Which among these three should I buy (or maybe I should buy them all)?

4. What brands do you recommend I should get for the answer/s in no. 3? How much should I buy (in grams or even size, if possible)? I use my laptop almost daily both for academics and gaming, if that helps.

5. Is it alright to ask for a color coded picture on where I should apply any thermal putty/paste/pad? I watched a couple videos and did my research but I'm a bit confused on a couple things.

6. Any tips to ensure a smooth-sailing journey?

I might need to edit this post if I ever have any other questions. Thank you to whoever decides to help me!