Repair render below dpc

[ADHDad]

Hi, I’m new to the forum. I worked in a foundry for 15 years as a mould-maker, using plaster to make jackets for silicone moulds, but I only have basic diy experience when it comes to plaster in the home. I need to fill some gaps in the exterior render of my property, underneath two door frames and below the dpc; can anybody recommend the best filler to use?

Thanks