iOS is probably the most locked down option you can pick. The EU even told Malus to open it up and Malus tried to fuck around. Now they might be in for some monetary justice, but that might take a year or two. Emulation was even only recently allowed, but only of old shit like Windows XP.
Android is still the most open, mainstream, phone OS out there. Get yourself a phone that can run a ROM like LineageOS, eOS, FairPhone or (if you want to give Google more money for surveillance) a Pixel to put GrapheneOS on it (easy process, you just need a browser and USB-C cable). That’ll get you more freedom to keep the phone alive longer and optionally become more private (if you can learn to live without Google).
To save money, you don’t even need to buy a new one. Get a refurbished phone. They are often 100-200€ cheaper than new phones and are sometimes as good as new.
iOS will lock you in, give you less options, and cost you loads to boot.