For electronic products, it should be enough to get the CE mark on your product, and it can be sold in any country. That is the point of the EU, that any company can sell it's products or services in the whole union, there are regulations, but they are union wide, not specific for each country.
Unless you were making something very special, that each country wants to and is allowed to regulate separately.
Taxes can be different, the VAT % is different in each country. But so is it also in each county or town in the US, and your people claim that this is the reason why you can't include taxes on prices in grocery shops, which is difficult to believe here for our people. So dealing with different tax rates shouldn't be big news for you? I mean... there are lots of online shops that know about different tax rates, it's not difficult. Or you could let someone else handle it for you.
If you sell products to all 27 EU members and sell above a certain threshold you will have to work with all 27 tax offices in regard to VAT. There is OSS for B2C but that comes with significant downsides.
Probably there are plenty of regulations related to safety and suitability regarding electricity, water, washing residue on dishes, etc.
Without being more specific, the only thing I can presume is that you were unwilling to follow regulations here.
I furnished and equipped my home a couple of years ago, and I had plenty of options for dishwashers, from multiple brands. Many different models at varied price points.
This tells me that serious companies have little problems to follow regulations to compete here.
Yes, the EU is not a country. Each country has their own government, with regulations of their own.
I am in favor of some sort lf EU federalization for this reason, there's a lot of redundancy.
On the other hand, you could just choose a country to operate, which is a normal thing to do. There are things I could find, for example, in France that I cannot find in the country where I live
It was good enough for the US.