Yes possibly IMO certainly Ulster
To be fair the crown did their best in the OTL to eradicate their culture. For example as mentioned the highland clearances, the banning of tartan, the banning of highland dress the concerted effort to discriminate against Gaelic so your argument is a little redundant because this attempted eradication occurred anyway. Short of genocide I’m not sure how could have been worse. Whole communities were wiped out due to the clearances, state and state sponsored discrimination. Indeed many families in light of these policies over night stopped speaking Gaelic in public and many even anglicised their surnames to avoid discrimination.
In terms of romanticism this happened in the OTL anyway due in part to Walter Scott - in a catholic dominated Stuart nation if this was possible and could be sustained then this would happen again.
Yes, this is my point. It was eradicated as a separate clan culture, a culture that was hated and feared among 'civilised' society in the lowlands and England. That then allowed it to come back as an admired "noble savage" culture that was part of Britain's general heritage.
A stronger clan system used to enforce a Catholic monarch on the UK would have had highland culture, clothing and music as symbols of the treacherous other and thus kept as part of a minority that would be overthrown in time.