[10] Kovachev was named captain for the Ludogorets U19 team in the UEFA Youth League in the first match from the Domestic Champions Path against Željezničar U19 on 27 September 2017.
[19] On 3 August 2023, Kovachev joined Russian Premier League club Akhmat Grozny on a season-long loan with an option to buy.
[22] Kovachev made his debut for Bulgaria U21 on 27 March 2018 in a European Under-21 qualification match against Kazakhstan U21, keeping a clean sheet for the 3:0 win.
[23] Kovachev received his first call-up for senior Bulgarian squad on 29 August 2018 for the UEFA Nations League matches against Slovenia and Norway on 6 and 9 September.
[24] He earned his first cap on 26 February 2020, coming on as a substitute for Ismail Isa during the second half of the 0:1 home loss against Belarus in a friendly game.