Your iPad can be safely charged using a high-output Power Adapter. While your iPad will limit the power that it draws from the Power Adapter to its maximum supported charging rate (~20W), a higher-rated compatible Power Adapter will cause no harm.
Using a higher wattage Power Adapter will offer no additional benefit for iPad charging, but does provide additional power capacity for other connected USB accessories which draw power from the USB bus. For example, a connected USB-C hub will typically draw 10W to run the hub, plus other connected devices (e.g., iPhone, card reader, wired keyboard etc.) will also draw power - their additional power needs being cumulative. As such, a high output Power Adapter has the capacity to both fast-charge your iPad at its maximum supported rate and provide sufficient power for other connected devices.
However, there are caveats…
Your iPad Pro supports USB PD (Power Delivery) Fast Charging, but does not support “QC” (Quick Charge) other proprietary Fast Charging standards. Unless your Power Adapter is certified as USB PD compliant, your iPad will draw no more than 12W (i.e., 2.4A @5V) or less.
Connecting cables must always be rated equal or greater than the maximum anticipated combined power loading of the devices with it used to transfer power.
Also consider that high output Power Adapters have the capability of delivering substantially more power than the Power Adapter with which your iPad was supplied. While it safe to use high-output Power Adapters with healthy devices, in the event of an unanticipated fault occurring, considerable damage can occur to connected devices, the Power Adapter and any surrounding materials of surfaces. For this reason alone, you should always use good quality Certified Power Adapters and cables.
Charge the iPad battery - Apple Support