The reason it's such a problem to be a problem from doris89592's blog

Many players looking to FIFA 23 Coins create SBCs are probably wondering what happens in FIFA 23 is it possible to change concept player positions? As there is a completely modern chemistry system introduced in this year's FIFA that disregards players who are not in the position so it may be difficult to determine if you have the right requirements for being a contender. 

If you want to know whether you are able to in FIFA 23 change concept player positions, make sure to follow the rest of this guide.Furthermore because of out of position players not contributing to chemically, those who would have gained from their club, league, or national team will not get any chemistry boosts.

It can be extremely frustrating when trying to build an SBC that has specific requirements for chemistry, as you don't want to buy an athlete from the market and then discover that the player doesn't meet the demands. It can also be frustrating when you are testing potential squads for your team, as any form of hybrid will cause headaches trying to fit specific players in.

The reason it's such a problem to be a problem in FIFA 23 is due to the more stringent requirements for chemistry. In previous FIFA titles, every position was assigned a number of "similar positions" which were able to contribute a percentage of the chemistry. 

So it was possible to cheapest FUT 23 Coins get a idea of how your team could perform with or without any modification to position. The centre midfielder for instance would receive seven chems at CAM and CDM, but with FIFA 23 this is no longer the case.