Trouble with abolishing the monarchy is you need to replace it with something. I'm no fan of the monarchy as an institution or as a collection of individuals, but if we abolished them tomorrow then you're giving the worst PM in my lifetime the opportunity to write a new constitution, and that idea fills me with dread.
If you were to give me a blank slate right now to reform this country's constitution, I'd be looking at things like PR, devo max, house of lords reform, an english parliament sitting outside of London etc. All of that is achievable and will definitely improve things. Abolishing the monarchy is probably not achievable, and has every chance of leaving us in a Tory led dictatorship, so I don't think it's a worthwhile fight from a pragmatic point of view.