CPU fan problem

Hi. I have more than 20 years old PC, Intel Core2Duo. I have the picrel fan. It has recently started making noise (to the point my ear facing the tower aches), I suspect bearings have worn out. In my previous experience of disassembling of a broken fan (not a CPU one, a usual case fan) .... I remember that they 1. are not disassemblable at all, designed to be expendables/consumables 2. have friction bearings 3. have come PCB with some circuit in them. Access to it is impossible without breaking the fan. Likely the CPU fan has some kind of speed sensor in it that usual fans connected using 3-pin connectors don't. Just wonder if I can cheaply (no computer tomography, 3D printing, CNC or custom PCBs, I cannot afford that, I simply don't have equipment and skills for that) replace the original fan with a usual casing one while keeping the radiator. I surely don't want to buy coolers on second market at very inadequate prices that will likely fail the same way my fan has failed.

Likely strongly related: https://www.intel.com/content/dam/support/us/en/documents/intel-nuc/intel-4wire-pwm-fans-specs.pdf

Should also be related: https://www.analog.com/en/resources/analog-dialogue/articles/fan-speed-control-techniques-in-pcs.html

Also related: https://site.cwc-group.com/specifications/intel-d60188-001.pdf

This CPU and coolers for it are not manufactured for a long time. You know, as long as soykaf stopped being manufactured it becomes an antique curiosity. For example DDR2 memory now costs more than DDR5 one, but memory is always golden and memory controller is high tech gear. Well, molding plastic is also high-tech, in fact it is the most high-tech part of every electronics, you can solder chips with an SMD hot air gun, well even BGA ones if you are lucky, you can order a multilayer PCB cheaply enough if you have schematics, but if some unique plastic part breaks ... you have no option but to discard the whole device. I hope that there may be some adapter being sold having the lower part like this one and the upper part allowing to fix any standard 4-wire PC cooler. Otherwise I suspect I'd have to try to just chop these 4 suspending elements and zip-tie a piece of plywood to the remaining ring. Though I'd prefer to avoid doing that. Has anybody of you done anything like that?

I also suspect that it can be motherboard electronics issue rather than cooler issue .... the noise starts after some time of CPU operation. But ... I remember the similar case ... where the cooler of PSU (of a different PC) used to make noise and to get rid of noise for some time (hours) one should have just allowed the noisy fan's blade to hit an object (I used tweezers for that). But it is not the case with this PC's CPU fan (I tried).

I have rebooted the PC. Rebooting the PC through ACPI doesn't stop noise ... but turning it off and then ON through ACPI does... I'm still not sure about the origin of the issue ... I have cleaned the fan using vacuum cleaner thoroughly, if the origin were particles subject to centrifugal force, they should have been sucked out. To prove or disprove it is electronics one need another 4-pin cooler or an oscilloscope, I have not acquired any yet and oscilloscopes are costly so I'm not going to buy them. BTW the behavior is the following: first there is no noise, after some time additional kinda-clicks emerge, first a little, then more, usually stepwise each stage starting suddenly. Also when the CPU is loaded it feels like the noise gets a bit quieter.