Stock recommendation for 7 years - Liquidity of around $110K

Here is the situation - I bought a house in 2022, with mortgage rate of 2.7% but with 10/1 ARM - so interest rate will change in 2032.
I never plan to keep the mortgage for 30 years - something about owning money with me does not work - I have another hours bought in 2017 for $330k and paid it off by 2020 - currently converted this to rental and with a market value of roughly around 500K ( thanks covid)
Coming back to the point, I have been saving money and have roughly around 110K towards paying off the house however I would be stupid if I pay off my mortgage as opposed to just putting it in one of high yield saving account or CD as those are paying more than what I am paying on my mortgage.

I am looking for recommendation of "safe stock" with a vision of 7 years where I can park this money and hopefully dont loose it all. Looking at your advise/suggestions/recommendations for the same.

Thanks.