I'm having a similar issue to this one: I have retrofitted my printer with a BuildTak sticker. I'm printing PLA at 60°C bed temperature - currently using a 0.3 mm nozzle, but I had similar issues with the 0.4mm nozzle before.
If I bring the nozzle close enough to the print surface to get a reasonable first layer, I need excessive force to remove the parts afterwards - so much force that I already have damaged the BuildTak in one or two places. If I lower the bed (the physical bed using the screws, not the temperature!) so that the parts come off easier, the first layer is very uneven and it takes 5-6 layers until the layers start to stack onto one another the way they are supposed to. What can I do to influence the adhesion of the printed parts to the BuildTak surface - especially to lower it in a controlled manner without changing the nozzle height?
When I was using BuildTac on a Monoprice Select Mini, I had to print with a hot bed (50 C or so) and then wait until it was cooled before attempting to remove the parts.
I used a set of very thin removal tools and a lot of patience to remove my parts. I would be careful to push only parallel to the BuildTac with one of the sharper tools. Once I was under the part, I could usually slide the tool under the part like a knife to separate the part from the BuildTac.
I was only using BuildTac on that machine because I damaged it's original yellow surface when I removed my first Benchy from that machine. Since then the BuildTac has lasted for months.