Hi sleepymolar,
Thanks for taking the time to share an update about your first few nights on your Tuft & Needle … I appreciate it 
As you probably know there will be a break in and adjustment period over the first few weeks as your mattress softens a little and you adjust to the “feel” of a new sleeping surface that is different from what you are used to (see post #3 here) but based on your feedback it sounds like you are sleeping very well without any discomfort or symptoms which generally means that the firmness is a good “match” for your body type and sleeping style.
If you are looking for a standard steel bedframe then post #10 here may be helpful.
Phoenix