I understand you have read a lot, but reading isnt going to give you all the information you need to make the descision ahead of you. Sniping in airsoft is not like videogames, sniping is for someone who has a LOT of patience and doesnt mind putting in 10x more effort for one kill because it helps the team out.
When I first tried out the sniper route I had a pretty good idea what I was getting in, I read A LOT, and by that I mean at least 40-50 pages on here, I stalked the most well known airsoft snipers and read every post they had, and talked to EVERYONE who had a scope/sniper rifle that I played with. I already had a good idea what real snipers and designated marskmen do, and I am very used to being outgunned and using tactics and smarts to win(5 years of paintball with a pump action going out with 50 rounds on me mowing speedballers shooting 15-20rps with well over 2000 rounds on them) and I also really enjoy using the sniper setup in videogames, and usually prevail because I am an intellegent and very strategical player.
when I first got into the "long range" airsoft weapons I spent about $1000 on this amazing m14 package that was the absolute best on the market. It had about $3000 put into it and had seen two gun docs to ensure it was going to perform as better than the manufacturers ever thought it could. Keep in mind this is a semi automatic rifle with full auto capabilities utilizing scope I left on about 2-3x. I played with it for a while, Tried "sniping" In areas that were just made for a good sniper, and I had limited success. I could shoot farther than others, but it was big, heavy, and while sniping I missed out of a lot of chances to rush up and do a lot of damage in favour of letting them come to me. Most of the time I ended up engaging people with 40 feet and using it on full auto doing short bursts...after a while I just ran around with my pistol and did a whole lot better...
Although discouraged I thought that a bolt action shooting a higher fps may be what I needed to snipe, so that I could hit anything that I saw and could shoot my way thorugh where I would normally push up. Tried it, was patient, set my bipod up and had good shooting form, shot 4 people from a days worth of play, and only 2 called themselves out(you could see the bb travel straight through the trees and hit them, they noticed something but it wasnt significant enough to be considered a hit, I dont blame as most gear will deaden the sound and impact a lot). I played with my aeg for the rest of the day, got 30+ kills in a quarter of the time I had put into sniping and was actually winning games for my team. I still could be stealthy and play smart, infact Ive had people who were less than 5 feet from me walk right past me only to get shot in the back when they were far enough that they wouldnt notice the sound as easily...
as for a pistol if it is a requirement for cqb you will need something that is cqb ready. You will be caught with your rifle out and will be required to use your pistol, and if its this giant clumsy thing you wont even unholster it before your screwed. Even with my aeg using a sling so I can just drop it and go for my pistol if I need to, its a lot slower than you anticipate it to take.
also, it takes a lot of energy to properly play a sniper. Just because you have a bipod up and are laying down doesnt mean it is going to be a walk in the park. You will require a lot of core strength, upper body strenght, and endurance to be able to maneuver and hold your rifle.
last time I saw a "sniper" was when some kid had a full ghillie suit. He carried his rifle for maybe 1-2 games and from then had it holstered on his shoulder until ready to fire, didnt hit a single thing all day, and tbh you could probably take him out if you were in a open field with no cover and were just using a knife...
My advice, listen to everyone else. I know you won't, very few actually take the word that advises against doing something you want to, but it willl benefit you if you listen.