I think I found my solution! Duh, not sure why I didn’t just Google it before! Bed Rails for Toddlers - Extra Long Toddler Bed Rail Guard for Kids Twin, Double, Full Size Queen & King Mattress - Baby Bedrail for Children (White XL)… https://www.amazon.com/dp/B077MQBS2Q/ref=cm_sw_r_cp_api_glt_fabc_B1ZWXWVMA4007PQZ9FW9
I am still curious about the use of blankets though!
As soon as they can climb the crib is time to switch. They are at far greater risk of getting hurt falling from crib height while climbing than they are falling out of a twin.
Some suggestions:
Bed Rails, you can get temporary Rails to put on the bed. bed rails this was just the first one I pulled up, I have no opinion on this particular one (or any as I never used one)
Place the old crib mattress on the floor next to the bed. If she falls, she lands on the bed.
Probably too late if she already has a bed, but we got a bunk bed to start, one that can be used as stand alone twins or stacked. We assembled the top bunk, with the Rails but used it as a stand alone bed. Rails kept kid safe, then when little brother was ready he got the "top" bunk and we assembled the "bottom" bunk for bigger sister.