You should always base your game around the way you play, in the main. There are core positions vital to the way you play that I wouldn’t be changing out just to suit the opposition- GK, CB, CDM, ST. However, naturally you Always make slight alterations, not necessarily in personnel, but in terms of tactics to counter the opposition you are playing and individuals they may have that are dangerous. That’s all fairly normal and any manager worth his salt would take into account opposition in that way. For example, if the opposition has a high quality winger, you may tell your full back to sit back a little. Or if they like possession, press higher on them etc etc.
In terms of actual personnel changes, aside from the “key” positions I’ve mentioned, I think other positions are always up for rotation regardless of suiting the opposition at hand by players competing for the roles. This rotation could occur because of poor form, or tiredness potentially, particularly in wide players. This means that I myself would accept changes in those roles to “play the opposition”. I wouldn’t however drop an in form player under any circumstances other than tiredness however, so would be annoyed to see someone who scored a hattrick the previous week dropped to suit an opposition team. Otherwise however, I would be up for rotation to get the best team out to beat the opposition, even if on paper it isn’t our “best team” overall. This could involve playing Forsyth over Malone if the opposition have a greater aerial threat, for example, or playing some more possession based centre kids if the opposition are likely to sit back, etc etc.