You should look into using eQRP which is a company that gets you the checkbook control of your retirement funds you're looking for to buy real estate, but their patented process allows you to avoid UBIT Taxes which will save you thousands compared to an SD-IRA. The main differences we found were:
1) How much you will pay in UBIT taxes on the money your funds make.
2) For SD-IRA you have to go through a custodian to move money and make transactions, for eQRP you are your own custodian (no middle man).
To be honest, the eQRP link below seems a little sales-y and looks like a lot of those "to-good-to-be-true-learn-how-to-make-money-fast-and-easy-and-more-so-much-more" website offers that we all come across in the real estate world and I just immediately close the internet browser window because I'm afraid I'm going to get spammed to death with emails.
Regardless, it is an interesting option for getting access to your retirement funds for investing in real assets and I know a lot of people in the multifamily space that have used eQRP. If you want, you can at least check it out as an option. Take care and Good luck!!!
eQRP information: https://book.eqrp.co/hsquaredcapital/