I don't think one can reasonably suggest a location with only the information you've given, but it is worth considering where your most senior employees and their administrative staff will be based. Not all countries in Europe have fully electronic submission of business documents, so you will need a physical presence that is actually manned. There are companies who can provide addresses or PO boxes for forwarding, but I'm not sure I would trust those with anything valuable - directors are still personally responsible for official communication.
As a British person, I suggest you be careful with incorporating in the UK. It is in many respects an excellent location for entrepreneurship, but the new Labour government and Trump's re-election in the USA means that our relationship with the EU could go either way. If you absolutely need public money from the Commission to make the business work, there are 27 countries that don't have the imminent risk of that disappearing!