It isn't possible to filter for "the same bet size on the flop and river", but you could filter for "4BB on the flop and 4BB on the river" - you'd have to do that for each case though.
You could do that with an expression filter in My Reports
cash_hand_player_statistics.amt_bet_f = cash_hand_player_statistics.amt_bet_r
That would require an exact match, but you could make alter it to make it "close", with something like:
(cash_hand_player_statistics.amt_bet_f <= (cash_hand_player_statistics.amt_bet_r * 1.1)) and (cash_hand_player_statistics.amt_bet_f >= (cash_hand_player_statistics.amt_bet_r * 0.9))
All simple filters apply to the active player, so do not apply to villains (unless you set the villain as the active player), but you can use:
Actions and Opportunities > [Street] > [Street] Actions Encountered with Sizes
.. to check the size of bets that you faced as a percentage of the pot.
If you do this, bear in mind that if a player makes a pot size bet (e.g. 10 into a pot of 10) then the amount you face is 10 in a pot of 20, so 50%, not 100%.