Eh? Tesla is third behind VW Group and Stellantis in the EU (fourth if you count Renault-Nissan, but that's a marginal case), and third behind BYD and SAIC in China.
Now, it's true that they're the biggest single BEV _brand_ in Europe (and second-biggest in China), but that's... basically just a different marketing approach. VW Group has multiple constituent brands mostly selling largely the same thing (SEAT/SKODA/Scania/Cupra/VW/Audi); it's no skin off their nose if someone buys a VW id3 or a Cupra Born (these are the same thing).
They sell better than any single car brand, sure, but much less as a fraction of the market. Their market share in Europe has been around 25% (compared to around 70% in the US). And it's falling. In March 2022, Tesla's market share was just 10.5%.
There is a large demand for EVs for multiple reasons (incl. the current energy crisis) and Tesla is not scaling fast enough. It's great that others also started producing EVs (consumer choice, price etc.).
But in absolute numbers it will not be easy to catch up, as batteries are a limiting factor.
Energy efficiency in modern EV brands also isn't very good, which requires putting more battery (and weight) into the car. (perhaps excluding Hyundai Ioniq-s)
Combined with fast scaling of the car production + high price of lithium batteries, this will limit how many cars can be produced or increase the car price for the consumer.
This may change if manufacturers will start improving efficiency or building battery factories for themselves. Which I think only VW is currently planning to do
