Tiktok account sending scam dms after clicking link from friend - is phone also compromised?

hello!!! last tuesday, a very close friend of mine sent me a link over iphone imessage to what appeared to be tiktok shop and said "i need you to open the link don't question it lol" my sister is always doing those shein and temu "have 5 friends click this link then get free item or x% off" so i honestly figured it was something like that. i felt no need to be suspicious since it was over imessage, if she had sent the same thing on say instagram i would have dmed but i figured imessage was safe (am i dumb?). after some googling, i've seen dozens of other people who are having their tiktok accounts send scam dms but i have yet to see any cause or solution. i'm wondering if others had a similar experience where they clicked on a link before the scam messages started?

i have 2 step verification on. i never received any sort of notification about a new device logging in but looking at my account it says its logged into an iphone 15 pro (me) and an iphone 15 (logged in same day i clicked the link - not me!). today around an hour ago someone logged in with an ipad which triggered a security email. i removed the ipad, and (after a stupid amount of time trying to figure out how since it wasn't caught as suspicious so removing it wasn't as simple as the ipad) i removed the iphone 15 from trusted devices. currently my "trusted devices" is blank.

while i am curious about how many people this is impacting and whether they had a similar experience to me (clicked link/no security alert), what i am most concerned about is my phone as a whole. i haven't noticed any other funny business and as far as i know i believe iphones are supposed to have pretty good security. however i have a lot of anxiety regarding this type of stuff so if something IS wrong i want to know as soon as possible so i can fix it. so is my iphone safe? if not, what steps can i take to secure it?

also if anyone wants to drop any websites/books/whatever on cybersecurity for dummies i would love to educate myself better to prevent future incidents and quell my anxiety.

any help is appreciated, thanks!