Welcome to the forum from another long-term T1.
Historically I always preferred to run ‘on the low side’ until about 10 years ago when I realised that my warning signs had taken a bit of a hammering over the years and weren’t as reliable as they had been.
With a lot of work, learning, experimentation and a bit of luck and a following wind (plus a switch to insulin pump), I managed to ditch the vast majority of my ‘low level’ lows and all of my severe hypos. My warning signs are much improved, but I really try to avoid any readings below 4.0 if I possibly can - while also not wanting to stray too high either.
I never found the ‘run a bit higher’ strategy worked for me as I could plummet from double figures into hypo without somehow magically stopping at 4.2. One of the best changes I made recently was to take precautionary action when I get in the high-mid 4s which gives any small glucose nudges I take a little more time to get going.
Glad you have access to Libre 2 - those alarms are a real bonus, especially overnight!