Will my UKCA marking also suffice on the EU market?

No. The UKCA mark is solely valid on the product market of the UK.

As of January 1st 2021, the UK is no longer a part of the EU and thus neither of the European market. Since the UK now has an independent market, the legal safety requirements of the products that enter the UK market will have to be certified separately. This means that UKCA marking will not suffice on the European market, and CE marking will not suffice for the UK market. If you want to sell your product both on the EU market and the UK market, you will have to obtain CE marking as well as UKCA marking.

If your product is CE marked and you have been selling on both of these markets prior to the Brexit, you will need to get your products UKCA marked as well.