The Ready State Virtual Mobility Coach is like having a virtual Kelly Starrett in your pocket.
The best thing you can do to help the muscles support the low back is regular movement. The more we stay stationary for a prolonged period of time the more likely your body will make adaptations in a negative pathway ex. tight hips, tight ankles, stiff upper and lower back, etc. This is likely why your low back pain flared up again during the Pandemic as many of us were moving and exercising far less and our bodies became more stiff. Try working up/downstream of the low back to start opening up and working on stiffness around those tissues. Here are some routines to get you started.
Roop also made a great video working on improving posture thats worth checking out: