Now that you determined the length, check the width of the shoe. The forefoot area is the widest and also the most sensitive area in terms of power transmission when cycling. The shoe should fit firmly in this area, but should not press under any circumstances.
Remember that the foot becomes slightly wider during longer training sessions. You should therefore have a few millimetres of room to manoeuvre so that the shoe does not press even after a long period of riding.
If the shoe feels too tight in the forefoot or leaves too much space for your foot, then this brand is simply not made for your foot. Don't make the classic mistake of chosing a bigger size, but better choose another brand of shoe. It may be an unpleasant truth at times, but some brands are simply not made for your foot.