Hi Samuel, thanks for your response.
I have been mainly trading the most liquid forex pairs, i.e EURUSD, GBPUSD, EURGBP, EURJPY, GBPJPY, USDJPY. Focusing primarily on M15 and H1 timeframes as that is what is most recommended in both the forum and by Petko (However I have also tested M5, M1, and H4 timeframes with worse results).
When it comes to generating strategies I have tested varying the OOS to accommodate for multiple scenarios where the start of the OOS period is both well before, after, and roughly around the date where I noticed profits started disappearing (towards the end of February). Neither of these worked better that any other (at least nothing significant). I guess the next thing I will try will be to generate strategies with higher OOS criteria as you mentioned, and only select those that worked best from the period since February.
Would you recommend any particular assets or timeframes that you have found success with since February?