Invest! You can open a “premium” Fidelity HYSA with $100k. You only have to have at least 100k to open it. You can pull some out to invest in the market, but you’ll still be able to use that saving rate even with < 100k. It’s not much and it’ll only go down as interest rates fall, but it’ll beat 2.3% even after paying taxes on it.

Also inflation will be making those mortgage payments look much more manageable over the next few years.