Firstly, you need to find a vacant position to apply for, they will be unlikely to create one for you to 'conveniently' slot into.
Are they in anyway likely or obligated to give me a similar paid role
The only time they would be truly obligated to find you a different role is if it had gone through a formal HR process where bad behaviour/bullying had occurred, they had acknowledged that wrong doing had taken place and to clean up,the situation, they might decide to redeploy you, especially if you say that option is amenable and if they value your expertise and don't want to lose you.
If you take matters into your own hands, and apply for a new position which is equivalent in grade and job content as your current, then your salary will likely stay the same.
If the role is lower grade they might move you across on the same salary as a temporary fix, but at some point they will probably peg you down. Or they may say "the role is x (lower) salary level, that's what we will pay you" and you'll have to decide whether to take the lower level, to resolve the situation and keep looking for better opportunities.