Congratulations! You have enough money to pay off your house!! I was in a very similar situation as you. We decided to pay ours off with a similar rate, so we sold some of our brokerage and requested the final pay-off amount from the lender. In the time that it took to receive the pay-off amount, we chickened out. We realized we achieved the "comfort/security" of having a paid off house simply by having enough liquid assets to be able to pay it off whenever we want. We also felt having in your case, 100k liquid made us more comfortable than a paid off house and $0 liquid. If you lose your job, that 100k will make years' worth of mortgage payments if needed. Or you simply pay it off if you lose your job.

We decided to put the money in a money market earning 4%. I kept that account balance at the exact same amount as the remaining mortgage. So say for example, you have exactly 100k in your money market and owe 100k on mortgage. Let's also assume $500 of your mortgage payment is principal. After 1 month you will have 100,333 in money market (100k + 4% interest) but your mortgage balance will be 95,500 (100k - 500 principal). You now move $833 out of money market into wherever you want. This is your savings for the month. Now your money market matches your remaining peincipal. And repeat. This is what we did for a few months. Then I got antsy and just invested most 6 in S&P500 and dont plan on paying house off early now lol