You can't connect li-ion packs in parallel just like that, they will be destroyed, possibly catastrophically. Having a feeling they are "more or less" at the same SoC when connecting together is not enough.
You can connect the li-ion cells parallel permanently, by carefully making sure they are at the same voltage within about 50 mV, but any chance of getting them disconnected and put together is a massive risk of forgetting to measure before connecting them together again.
Example calculation:
Typical 18650 power tool cell, DC resistance at room temp 20 mOhm, max specified charge current 2.5A, contact/wire resistance total 10 mOhm.
Cell 1, 80%, 4.00V
Cell 2, 60%, 3.80V
Current when paralleled: 0.2V/(20+20+10mOhm) = 4A, exceeds max charge current, damage very likely.
Example 2:
Cell 1, 100%, 4.20V
Cell 2, 0%, 3.40V
Cells are warm, DC resistance is only 10 mOhm, connection is solid with only 5mOhm resistance,
Current when paralleled: 0.8V/(10+10+5mOhm) = 32A, instant destruction of the cell, cell safety systems are likely to react and prevent a fire, but the cell is volatile and dangerous after the fact.
Use separate chargers and separate loads so they are never connected in parallel directly, or decide to build a big enough pack with permanently paralleled cells.