Thank you very much for the intricate and helpful answer. The thing is, I tried using InstaRanker and disabled my two-factor auth when adding my account (as prompted), but re-activated it right after. When it started its activity (likes only), I got an IG text message with a code every time it liked something (it still worked).. What could that mean?
I wish I found something like Instagress again, every single similar alternative I've found had some weird bugs that would make it a nuisance to use. InstaRanker is the closest thing I've found but it's got that issue, damn.
You're welcome.
You wrote "I got an IG text message with a code every time it liked something (it still worked)" Sounds like it was a verification message, like one sent from IG website while trying to login where IG tsays "looks like something suspicious was happening with your account" and then you are asked to be sent a code by SMS or email. If you were on the IG website trying to log in you might see that message as I just typed it here.
Web-based bot services usually tell the user if they get a message like that to try to log into their account online or on the app and do whatever IG asks to verify the account or action. You might ask support for help with that, of course, I don't know exactly what they would need to do to authenticate their access or actions as authorized or legit.
I don't know of a web-based bot service that has ever asked users like me for that verification code or repeatedly provoked SMS verification. I'm not saying you never would be asked or never should give the code out to app support, only that when verification actions are asked for either the bot just tries to handle them theirselves or tells me to go to the app / bot or IG website and log in and do whatever is being asked for verification.
For clarification of course send the app / bot support people a detailed message asking for help. Their bot may be trying to handle error messages and not doing so very well, or they may be using proxies that are not working well and provoking verification actions. They may say you should use more conservative settings, and maybe you should, there's many interacting factors that can provoke verification messages like this. Normally the bot will notify you though somehow that verification is being prompted by IG because this kind of verification requires access to the account's contact email or phone which the bot won't have access to, only you would have access to that email or phone number.
If nothing else, you might try again doing whatever provokes the SMS message and at the same time look at a phone or tablet logged into the IG app and not doing likes or follow/unfollow/DMs, just try changng screens or viewing accounts, and see if you get a message asking if it was you logging into some other location. If you get that message, you want to say "yes its me" if you know the action was authorized by you. Don't -- do not -- say "it wasn't me" unless you really want to ban or block the access attempt, which may ban or block the bot from using that unfamiliar / distant / foreign IP address & location from being used by your account.
It should be safe to simply browse or refresh a screen on the app while the bot tries to do actions on your account so long as you aren't doing likes/follows/etc at the same time you are trying to log ino or do actions through the bot. That would be similar to a user being logged into IG through a phone connected by mobile data while being logged into a tablet on residental WiFi, as I'll describe in the next couple paragraphs.
I would tell the app, if it were me and I wanted to say the access was legit, that the login was "me" meaning authorized by me. If it seems like the location the app says you are in is absurdly far away, like in another country or thousands of miles away, I might still say "yes" if by timing I knew the access came from an app or bot I was using, but I would definatly tell the app/bot support that it's saying you are logging in from some location suspiciously far away and they may want to use a different proxy location or if you can change your proxy location / choice you may want to do so.
That's how IG prompts users if they say try logging into a phone using mobile data which may show a completely different IP and location which may be hundreds of miles away while a tablet -- for example -- running off residential WiFI is logged into an IP address that is physically right where you are. If you can do that successfully and say the action was authorized by you, that may be enough to get out of these verification prompts & SMSs at least for now.