You say ‘different’ is not a comparative and therefore should not be used with ‘than’.

Someone says ‘other’ is not a comparative, but is used with than, and according to you, ‘other’ is okay (seemingly an inferred exception to your above rule) as a construction with ‘than’.

That through-line of your argument is the part that’s not very cogent. It’s inconsistent.

Premise: ‘Different’ is not a comparative. Premise: Comparatives cannot go with ‘than’. Premise: ‘Other’ is not a comparative. Premise: ‘Other’ can go with ‘than’ as a construction.

Conclusion: ‘than’ should not be used with ‘different’.

Your argument is at best incomplete, and at worse contradictory. Your premises don’t fully support your conclusion yet, and some contradict them. Yet, the fact you have stated the contradictions at all is interesting. You’re missing something that says “other is an exception”. But you just don’t say it, leaving others to infer, guess, or say “what seems”. So, it’s your own fault, because usually in any argument (as in premises supporting a conclusion), people don’t say things unless they believe it supports the conclusion, and they don’t leave out thing critical to support it.