When bitcoin saw the maximum fee required for getting confirmation within next block?
Depends how you define "getting confirmed within the next block". A reasonable estimate that a lot of people use is to be placed 0.1 MB from the tip. This is not the same as the highest average fee, the most unconfirmed transactions, or the largest mempool size in MB. As an extreme example, the mempool could have 100 MB of 1 sat/vbyte transactions, and a 2 sat/vbyte transaction could put you 0.1 MB from the tip. Similarly, the mempool could have 1 MB of 100 sat/vbyte transactions, and so to be 0.1 MB you would need to pay a fee of >100 sat/vbyte.
If you look on
https://jochen-hoenicke.de/queue/#1,all, it only lists fees up to greater than 2000 sat/vbyte. The peak was actually on December 22nd, 2017, with over 42 BTC of transaction fees at a rate higher than 2000 sat/vbyte.
If we look at the blocks mined around that time, for example
block 500546, the transaction with the highest fee in that block (
https://blockchair.com/bitcoin/transaction/285012743) is a whopping 10,120 sats/vbyte.
It's impossible to say what fee would have "guaranteed" entry in to that block, especially as most blocks also continue some "sub-optimal" transactions. For example, the same block above also includes some transactions with fees of around 400-500 sats/vbyte, despite the fact there were over 5,000 unconfirmed transactions with fees over 2000 sats/vbyte they could have picked instead.