While downloading a modded IPA for personal use is rarely prosecuted, you are violating the and Tinder’s Terms of Service (Section 3.1: "You may not copy, modify, or reverse engineer any part of the app"). Tinder has successfully sued developers of modded IPAs, and while they don't target end-users, they do blacklist your device permanently.
Most "Tinder Plus IPA" files available today are either fake (malware) or only offer cosmetic changes. They do not give you the true server-verified features of a legitimate subscription. tinder plus ipa
This is the biggest danger. Modded IPAs are created by anonymous hackers. Because Apple’s App Store review process is bypassed, these IPAs can contain: While downloading a modded IPA for personal use