To attach images, host them on a public server e.g. Dropbox or imgur, copy the link, then use the Image button in the menu bar to paste the link between image tags.

The G29 mesh bed compensation will only work well if the effector tilt doesn't vary significantly with XY position. Otherwise the tilt will alter the relative height of the IR sensor and the nozzle when the sensor triggers. G29 must be used after the usual G32 delta calibration, not before or instead of it.

I suggest you stop using G29 mesh bed compensation for now and use the same calibration settings that you used before. The printer should then behave as it did with the older firmware. On a Mini Kossel you should not need mesh bed compensation anyway. It's larger printers that benefit most from it.

Regarding print adhesion to the bed, probably the best thing you can do is to change the bed surface to PEI or PrintBite. Note that if you use PEI, then it must be painted black on the underside in order to work well with the IR sensor. If you choose PrintBite, choose the opaque version.

There are now other types of Z probe available that use the nozzle itself as the probe, so they are not sensitive to tilt as the IR sensor and other offset-mounted Z probes are.

HTH David