Are you doing PF exercises as well as using your pessary? If you dont keep your PF strong then a pessary isnt going to stop your prolapse/s from progressing.
You could look at other pessaries yes but you will still need to address any PF weakness.
Also, has your Urogyne explained to you why your prolapse/s have got worse? Is there a reason... do you have other abdominal pressure like are you lifting wieght at work or home regularly, do you run, have chronic cough or are you constipated? Look at other reasons that could be putting more pressure on your pelvic organs and PF.
Have you seen a womens physio therapist? Ask your Urogyne to refer you to see a PT and start to look at why your prolapse/s are getting lower.
If you have done all you can to halt the lowering of your prolapse/s then another pessary could be a good idea if you dont want an operation at this time