I can't speak for the A03, but others should be similar.
My S10 will fast charge and my S21 will fast charge and super fast charge.
For the S21, it needs to be set and the settings are under Settings/battery/charging settings for the S21
HOWEVER, I have found that some "fast charge" cables do not work.
I have also found some "fast charge" adapters don't work and some that will shut down because they can't output their rated current.
In order to fast charge or super fast charge, the phone must communicate with the adapter. The cable or the adapter might be causing a problem with that. For SUPER fast charging, you must be plugged into a PD adapter.
For fast charging, the cable and adapter must be rated for QC3 operation. For Super fast, it must be a PD adapter and the cable must be have USB3 C connectors on both ends to use it. I would also recommend a GaN charger.
[link|https://www.aliexpress.us/item/3256805582075967.html?spm=a2g0o.store_pc_home.hotSpots_2006835805816.3&gatewayAdapt=glo2usa4itemAdapt|The one I have|new_window=true] is unfortunately no longer available on AliExpress, but you might find one similar.
I can tell you [link|https://www.aliexpress.us/item/3256803415006471.html?spm=a2g0o.order_list.order_list_main.132.31ae1802HV1TGi&gatewayAdapt=glo2usa|this cable|new_window=true] works for QC3 fast charging.
If your charger doesn't have a display on it as mine above has, buy an inline monitor. That way you can tell instantly if the fast charge is working. Voltage will start at 5V but will change to 9V for QC3. It may go to 12V if it is a newer QC protocol.
[link|https://www.aliexpress.us/item/3256805231853731.html?spm=a2g0o.order_list.order_list_main.163.31ae1802HV1TGi&gatewayAdapt=glo2usa|This cable|new_window=true] DOES NOT work.
Niether does [link|https://www.aliexpress.us/item/3256805388975486.html?spm=a2g0o.order_list.order_list_main.173.31ae1802HV1TGi&gatewayAdapt=glo2usa|this charger|new_window=true].