With a direct connect pump, you will probably want to stay with the same type/brand so that it will fit properly. It also sounds like you are worried that there will not be enough flow rate to vacuum if you downsize the pump. However, any pump should be able to run a vacuum properly and circulate the water. Those functions usual do not require a high HP pump.

This looks to be a direct replacement for the pump you have: https://www.poolparts2day.com/store....26&pid=20&cart

If you want to downsize by one size, then you could go with this one: https://www.poolparts2day.com/store.cfm?pid=20&id=525

I believe that you can reuse your old pump basket on either of these pumps.