So, modules. Shiva modules are available from Final Lament which seems to be a permanent UQ. Their drop rate is reasonably decent from that, and you only need 40 for the whole Klauz unit set so even getting them from the market is probably going to be affordable for several months. I'm going to set those aside.
Exegul, Mitra and Varuna modules are the biggest bottleneck to making Klauz units, which are depending on who you ask either a requirement or highly advised for much of the endgame content. They are also available from Final Lament but I've received possibly none from it after a few dozen Shiva modules so I'm confident their rates are significantly lower. They are primarily available from Divide Quests. More problematically you need way more of them. 100 for Varuna and Mitra, 150 for Exegul.
The weekly point rewards from Divide Quests give 3 modules per week per character. There are a couple one-off titles that give 5-10 of each as well. This means anyone starting today with one character and making a quota every week would need to wait up to 50 weeks until late Spring 2022! If they hurried to take advantage of the remainder of the EXP boost campaigns going on or levelled alt characters like crazy after NGS released and with no boosts, this could be reduced to around 16 weeks with 3 characters and 4+ hours per week (more considering they probably won't be consistently getting full 100% S ranks), which still takes them into September.
Modules can also drop from Divide Quests directly. Excepting Stage 31+ there is one module-dropping boss on the fifth stage (so about 15 minutes per chance) and if you can defeat them before time runs out they have a low chance to drop 1 module. In a couple dozen runs, most of which I have defeated the boss, I have received almost no modules. I do not have any confidence the drop rate is worthwhile enough to support farming when Divide Quests are not active enough to allow either fast runs or the method to guarantee Exegul (and Varuna?) fights on Stage 31.
More on that: There's a way to condense the grind for Exegul / Varuna modules when Divide Quests are highly-populated and have altruistic people willing to idle in the quest when one of the Stage 31 options is their Suppression, so other parties can run it repeatedly for a guaranteed module. But on a smaller ship, the wrong time of day and/or without an active endgame alliance (whose members have probably already finished the grind at this point), the quest search for Stage 31-35 looks like this:
So to some players that's already not an option and it's not going to get better after NGS arrives. Solo and without endgame gear, your options are to manually run Stage 21-25 and hope for Varuna or Mitra (if you can defeat them in time) or Stage 26-30 which at least guarantees both and even if you can only defeat one before time runs out I have got a module from that. But that's still around 15 minutes for what amounts to a low chance of about 0.3% of overall progress. Getting all the modules this way would take over 85 hours even if the drop rate was raised to 100%.
I believe for the most part at this point players have either had Klauz units for a long time thanks to having the freedom to farm modules back when Divide Quests were more populous, or they've given up on ever getting them because they missed that boat and now it's even slower than the intention for the grind and with NGS 2-6 weeks away they don't feel it's worth what the grind presently is.
The volume of modules required, the low weekly allowance, the very low drop rates, and the short amount of time before Divide Quests dry up even more than they already have means I assert the provision of modules should be raised, either as a campaign prior to NGS (for those who'd like to make a last push to earn them, and with a presumption that Divide Quests will be dead after that campaign) or just permanently because there is no point to this being an extended grind after NGS arrives.
I would suggest raising the weekly reward from 3 to 10 (maybe 15 for Exegul), and/or changing the drop for defeating bosses from 0-1 (mostly 0) to 5-10 with an additional 5 for Stage 31+. This would sustain Divide Quests as a stepping stone to the other OG PSO2 endgame content going into NGS without simply obsoleting them by making modules available through a Weapons Badge exchange (or even worse just doing a Klauz unit handout).