You can strengthen pads significantly by putting a few via’s in them.
This is common practice for the mechanical pads for SMD connectors.
When soldering wires directly to pads it is a good idea to put them through a hole and solder them on “the other side”, or even put them through 2 holes, which give a quite usable stress relief for the solder joint.
(Glue the wire to the PCB?)
Have you cosidered drawing the zone outlines in a CAD package, save it as DXF and then import it in PCBnew?
(I’m not sure this works, but it might be a good idea if it works.)
Try the TS100 From Ali / Ebay.
This USD 50 Iron is probably better than the USD 300 Weller PU81 I bought a few years ago.
All Irons with adjustable temperature have a form of closed loop control. It is the only way to control the temperature.
2 important factors are the power of the Iron, and the speed with with it heats up (also reacts to temperature disturbances). The TS100 is quite good in both aspects.
For better Irons you need to go to JBC or such, but expect to pay then USD 500 or more.
The USD 50 TS100 seems to outperform most of the USD200 class Irons.
I also saw some youtube reviews where it was deliberately destroyed, overheated , tip filed down etc. It looks a quite robust Iron. Replacement tips are also quite reasonable in price, Only limit is that there are not very many different tips available for this Iron.