Take a hacksaw or bandsaw and cut each cassette through the middle, between cogs

Take a credit card (the perfect thickness for the material removed from sawing) and cut a disk to act as a spacer

Before you cut the credit card, use it to buy a cassette with the tooth-count and spacing desired

Yes

If you purchase an 11-32, just put those last 3 gears on your 12-25. You're going to need that 3-gear-one-piece portion because otherwise it's not going to shift well from a 23 to a 32. You'll need a longer chain and probably a long arm derailleur, but those won't overcome the need to have a couple steps between 23 and 32.

Also, do you have a 34 small ring up front? That will work wonders versus a 39.

There are a lot of rigs you could set up, but just know that cyclists for years have overcome your problems and then found a way to sell the solution. So, if you can't buy it, someone probably figured out that it wasn't a viable solution.

11-12-13-14-16-18-20-22-25-28-32T
12-13-14-15-16-17-18-19-21-23-25T

If i take last 3 cogs from 11-32 and put it on 12-25 it would be
12-13-14-15-16-17-18-19-25-28-32
Or what could i do?

Go 18 - 22 - 25 - 28 - 32

When there are large jumps, you risk the issue of dropping the chain off the hub side, or more likely, it won't go up unless you're at an easy power, which you won't be if you're climbing a hill that requires a 32t cassette.

I saw videos on youtube that people are using this wolf link and put cassetes from 11-40 with nonproblems
There are also big jumps
I just meed one cog gradation and few vogs for hills

Back your B-screw out and adjust the limiter screw on your existing derailleur and you won't need a wolf link for a 32t ring. I have that adjustment on my road bike right now. It makes a little noise, but I'm only using it for seconds at a time. It's not my most pro set-up, but it works. The further you move the derailleur away from the cassette, the more likely a delay in shifting. So you don't want to sacrifice shifting in 90% of your race for a benefit in 10%. Also, much of this is outside of the manufacturer's specs, but their recommendations are for durability, not possibility.

I'd go 17-19-22-25-28-32. The steps between gears would be more consistent.

But last question

Can i put it together with this two cassetes that i have?
They are both from shimano 105 r7000
Just take one cog and one cog and put together. And spacers between them?

Yes. As long as there are 11 cogs w space in between and the smallest is threaded (12t), then it will go together.

Yes. The first 2 from a given cassette have the spacer built in, so I'd use the two from the 12 and 13 from your 12-25. Use the joined 25-28-32 from the 11-32 and then mix and match the rest of them to get the gear spacing you want, avoiding large jumps (>4) where possible.

At this point, you just need to go play with it.

Tenks.

Is it Shimano?

People seem to only be considering the number of teeth and not the fact that each cog has multiple versions (a vs b vs c) of ramps.

You need to match them up in a way that the ramps are the same at the transition cogs that you're swapping. Otherwise the cassette will barely shift in those cogs.

Can you explaind more about this?
I read something about this verisons a b and c
But dont understand much :(
Does it need to be everything in one letter?

your "mixed" cassette will be:

12-13-14-15-16-18-20-22-25-28-32T

hope this helps

in simple words: if one cog stays in a certain position in a given cassette (say position #7), it must stay in the same position if you move it to another cassette

"jumps" must increase ramping up in the cassette: 1-1-1-1-1-2-2-2-3-4 = good

1-1-1-1-1-1-3-4-3-4 is not going to work well

You can run an 11-40 with a long cage R7000 or R8000 derailleur. I've used it once trying to do a really steep climb (Brasstown Bald)

I've been mixing and matching for years. Sometimes it works perfectly and sometimes it is not quite as nice. Most recently I took an 11-34 and mixed it with some other random cogs so that it was a 13-34. (I have very little use for a 53-12 anymore, much less and 11.) It works perfectly and I don't waste two gears that almost never get used.

The cogs that matter are the 1st and 2nd position and the last three that are on a carrier. The 'free' cogs in the middle are easy to switch out.