S-400s are potent systems but there are more than adequate countermeasures. Will be circumvented same way the S-300s were circumvented. Besides, the Chinese field the S-400 and PAF can train against it there and sharpen countermeasures.
It’s not insurmountable as is claimed. Definitely not a one-way ticket as you suggested
Americans have personnel deployed at 2 PAF airbases to look out for any Chinese. PAF F-16s are not allowed to exercise with PLAAF.
Will the British or Europeans be any different ?
As far as countermeasures are concerned, what does the Typhoon possess to blind radars that aren't the pulse-doppler ones ?