ASML developed the immersion part from 2001/2002 to 2006 (HVP), but they'd been selling dry ArF machines for years then. Nikon took a bit longer and Canon never managed. So maybe the base rate for developing ArFi almost from scratch (so not starting from dry ArF) is more like 10 years? SMEE probably started working on ArFi around 2020 or a bit earlier, say 2018. So that suggests 2028 or so, meaning perhaps 25% that it happens by 2026.
The timeframe is very short (~1 year). Getting an HVP-suitable product will likely take some amount of time after a first product is launched or sent to fabs, and we haven't heard of that happening.
Why do you think you're right?
ASML began to properly work on EUVL in 1997 and released a commercial product in 2019, so that's 22 years. I'm guessing a similarly concerted effort began in China around 2018 as patents / research pubs started increasing markedly after that, plus there was the US export ban on EUVL around that time. That's a base rate of 2040, or perhaps ~5% that it happens by 2030.
But it's probably a bit easier the second time around, e.g., ASML and its suppliers had many options in terms of technologies and materials and it was unclear early on which one was best, whereas it is now clearer. Also, China may have access to various ASML documentation and other material related to ASML, through hacks. Also, China has poached and will keep poaching ASML and other relevant researchers and engineers.
On the other hand, the Chinese litho industry is much weaker than ASML and its partners were in 2000. They haven't even delivered good DUV systems, and don't have the years of feedback from fabs that ASML had.
Also: The Chinese economic outlook is fairly bleak, which may reduce its capability/willingness to sustain R&D in the longer term, similarly to the situation for Japan in the 90s/00s. Japan had a lot of EUVL research in the 90s, invested substantially into developing EUVL, and still failed. The ASML effort was a multi-country effort; China is mostly going it alone.
Why might you be wrong?
There does seem to be a concerted effort to develop EUVL in China across research labs and industry. It has been done before, and China benefits from it having been successfully done before. Chinese manufacturing and science is generally strong and not to be underestimated.