SOLVED my cold lower back while winter biking baselayer

The problem i have is the exposed lower back. Most notably when I am biking.

TL;DR Get polyester longsleeve baselayers that are oversized. This solution would be the best value and most flexible. Other options are one piece suits.

Why get the longsleeve baselayers?
Tuck them in. I mean it is not as cool as owning a specialty made ninja suit, but it does solve the problem.

It also has a number of advantages, namely that you can have multiple. That you do not need to be beholden to one specialty garment. They are more, so you can use them in other seasons. Like if I get a full body suit, I am pretty much only wearing that in winter. And while that might be a long time, it is not all year. Whereas a longsleeve, you can wear as a sunshirt too. In fact, I have worn them when it is really sunny out and they keep you cooler, plus, no need to wear sunscreen on most of your body.

If they are not long enough, just get oversize ones. Those are easier to wear and layer too and wash and then i could have multiples. having a hood is nice for winter because I pretty much always have a hood for warmth.

There is something warmer about a hood vs a beanie.

patagonia capilene 4 one piece suit - $199
Mountain Hardwear Stretch Thermal Suit - $150
The North Face Wool Base Layer One Piece - $230
Airblaster Ninja Suits - $109

Other options?
Overalls are another option - but it turns out that I have a few pairs now: 1) the nylon uninsulated ones that i got as a gift. 2) the insulated nylon oversize ones from hunting.

These cover my 'windproof' layer as much as I need it now.

What are these things called?
Another issue I had is that I could not find a good search term for these. Here are a bunch I tried.

fully body baselayer - this one made the most sense, but it was hit or miss
thermal suit - pretty good, seems like the one that returns the pricier and outdoor style brands like listed above
one piece suit / body suit - not very helpful, mostly like adult stuff
onesie - this was mainly like cosplay outfits and 'silly' ones, but there were some results here
coveralls - mainly the outer garment
long johns - classic, this one took a while for me to get to, but it is the best term probably. i realized i wanted sweat wicking baselayer vs like a comfortable cotton baselayer. these are typically cotton baselayers
long underwear - same as long john, but included mostly the two piece styles...which I guess I just came to the conclusion would be better for me anyway
thermal onesie - more accurate, but not much
full body baselayer - this is probably the most accurate, but mostly yielded like ski results and really random stuff