If you only see count as an option it’s because Glide sees that value as text. Check to see if your number is stored in a text column along your flow. Otherwise add a math column in between and simply multiply by 1. This should force your value to be a number. Then do your rollup on that new math column.
Your math formula is incomplete. It should be amount * 1, and then use a replacement for amount.
Where is that being added? If it’s just display formatting that’s applied in the Glide Data Editor as part of the Number column configuration, then that should make no difference.
To @Darren_Murphy’s point you shouldn’t need the math column if you find the culprit. Were you able to figure it out without the additional math column? Sometimes the devil is underneath the column… somewhere in your flow it may appear as a number column if it comes from say GSheet but it needs to be edited and saved again to force the format type
Everything is working now, I just substituted the formula column for the math column. But its strange as I went through the whole flow of where and how I capture the data and didnt see any point where I may have saved it as text. I could be missing something but everything is working now