For what its worth, Aol & Yahoo emails are the same since they were merged together in 2016. Verizon bought Aol in 2015 and then purchased Yahoo in 2016.
If you want security/privacy, go with Protonmail or setup your own server.
Gmail, Yahoo, HotMail, Aol.... all use algorithms to read your emails, this information is then used to sell targeted ads. Other data collected is made "anonymous" and sold to 3rd parties for whatever. If the product is free, then you are the product...
Throw in another Thunderbird vote for stand alone email client.
I also have a couple Protonmail accounts. Gmail is used for stuff I don't mind getting spammed for, I only use the protonmail accounts for more serious stuff. No online shopping or nonsense that is going to get my data sold. My only regret is, when I used to be an insurance agent, using my primary proton mail for setting up all my contracts with various insurance carriers - its been over a year since I let my license lapse and I still get shit from them, despite reporting spam and blocking. They just send from other email addresses.