There a quite a few options here, and the details will determine what's available to you. There are two main pathways for this - Delayed Financing and cashout refi's.
With delayed financing, you can get a mortgage that's treated as purchase money financing after closing so long as no lien was put on the property during the purchase. In other words, if you buy with true cash (meaning not hard money, no lien was put on the property at purchase, etc), then you can get a mortgage for up to six months after closing based on the purchase scenario (basically a cashout refi). You cannot finance more than what wouldve been available in the initial purchase or use any improved value or new appraisal to increase the loan amount.
With a Conventional cashout refi, you will need 12 months of seasoning from purchase; however, the LTV will be based on the new appraisal amount, not the original purchase.
Additionally, there are several DSCR lenders who have various products for this, but most have something similar to Delayed Financing as well as cashout refi's with seasoning typically around 6 months.
I generally don't recommend holding real estate with all cash unless there are extenuating circumstances. If you want to be conservative, stay around 50%-60% LTV, especially if your cost of debt is lower than your cap rate, as this will lever your ROE. Generally you get top tier loan pricing at or below 65% LTV. Ultimately, a lot of your decision will hinge on your strategy and goals.
As far as whether rates will be lower in a year, that's anyone's guess. It's just as possible (and just as likely, in my opinion), that rates are the same or higher a year from now. The future is unknowable.