I don’t have this specific problem (yet!) - I have more trouble passing water.
However, what does it say on the product instructions about how frequently it is safe to use it? Surely, if there were any adverse consequences associated with frequent use, there would be a legal requirement to state this?
I’m sure some people with MS use an enema-type system (not a suppository) daily or every other day for this problem.
I’m guessing that in a healthy person, such practises might encourage your bowel to be lazy, but if your bowel muscle already isn’t working anyway, what more can it do?
Have you considered seeing a continence nurse for advice about how to properly and safely manage the problem, rather than using “off-the-shelf” remedies, whose long-term effects you are unsure of? The nurse might be able to reassure you that, if it works for you, what you’re doing at the moment is completely safe. However, if it isn’t, she should be able to recommend something else.