Just spitballing this idea:
Current basis for btc 4 year cycles is based on the fact that we are assuming movements / time frames with repeat themselves or at least rhyme with the past movements, in stages of exponential highs, correction, accumulation, and continuation. And while those happen, there's no rule that it needs to happen with a similar pace.
I know we are assuming that btc cycle lenght is based on Bitcoin technical FA (halvenings) and that real world events would not affecting the cycle lenght. But Covid 19 just halted nearly everything in this planet for a very long time, so why wouldn't it affect all market cycles with it? Bitcoin wouldn't live in the vacuum when it comes to market conditions.
It depends, as you say bitcoin is not in a bubble and now it is part of the financial markets, so if the pandemic affects the economy then bitcoin can be affected by it as well, however I see the possible impacts of the pandemic on the price of bitcoin as positive.
Even before the pandemic governments were heavily indebted and after the pandemic this is way worse, the taxes they got went down and the economy slowed down to critical levels, this means that all the signs point towards a long economic crisis, which is the very reason why bitcoin was created, so I think the 4 year market cycle could be broken in a positive way for bitcoin.