What Deye Cloud does well
It is made by Deye for Deye inverters. Its manual describes remote control of battery settings and work modes, and quick actions such as Force Charge.
Deye Copilot schedules charging from your rate plan, flat or dynamic, and shows predicted solar and battery curves. Deye sells it as a subscription add-on, available in select regions.
Where they differ
Copilot works through Deye Cloud on the internet. Solsidus plans in the box at home, on your network, and keeps planning and charging if your internet is down.
Copilot is a subscription. Solsidus is bought once; EBB Lite needs no subscription.
Deye Cloud is for Deye. Solsidus supports Deye today and is being built for Growatt, Victron, Huawei and Solis too.
Run one planner, not two
Copilot and Solsidus would both set when and how far the battery charges. Use one of them. You can keep the Deye Cloud app for watching your system either way.