Seeing Erdogan is goner, I wish we had a nuclear development program and we tested it underground 3 months before the elections. We could be apologetic and blame it on Erdogan after the elections and maybe fend off the sanctions. This might be a harebrained idea but I can't help but speculate
The critical (capex infra) elements of turkish WMD program should have been started in ~ 1980s if you ask me.
i.e Get a couple reactors, and get plutonium (239) production started (using the neutron flux of reactor and create a "bed" design around it)....start stockpiling that plutonium till design program catches up. Pu-239 half life is 24,000 years so its fine....you just need U-238 (i.e regular uranium ore) supply plan.
Design program would not have been too difficult for Turkish science, engg and technical pool in 90s-current.... then you just sit on the design ready to test/assemble much like what Japan (definitely) and South Korea (likely) have achieved....and maintain US umbrella above it for now (but have very useful fall back option now....you can only trust yourself in the end).
Centrifuge route (U-235) is much more blatant one even back then (given NSG, NPT already kicking in)....so probably less ideal compared to cover Pu-239 (more dual purpose) would have provided through civilian reactor expansion program.
Now everything is watched*, noticed right away (reported in mass media eventually) and sanctioned....and Turkey is long term NATO member etc...
There will have to be significant political moves by Turkey that precede gathering + establishing the (fissile) material production capacity (i.e either reactors or centrifuges or both).
I don't see those being easy... this stuff is strategic and brings strategic costs too.
Lot of stuff in geopolitics is you gotta be one of the early ones with your leg in the door (strike the iron opportunely when it is hot)....later on because others jammed their leg and then went through that door, everyones watching it lot closer etc. Hindsight is 20/20 etc.
*IAEA safeguards even in Russian VVER Turkey is getting now...