Can I make a ammeter using a voltmeter and ohmmeter that would work in parallel to the device?
Ohm meters work by injecting a small current into the device and reading the resulting IR drop. So if something else is also forcing current through the device, that would disrupt the ohm meter’s reading. Unfortunately, since you don’t know what the current is then you can’t determine that resistance either. So you can’t solve for the current.

If you have a known resistance inserted in line with your circuit, you can measure the IR drop across that and determine current without breaking the circuit. Many designers will insert a low-value resistance in line with the power supply to make it easier to measure current.