[2] At the 2021 European Short Course Swimming Championships held at the Palace of Water Sports in Kazan, Russia in November, Lamberti started his competition on day one with an Italian record of 22.91 seconds in the 50-metre backstroke prelims heats that qualified him for the semifinals later the same day.

[14][15] In his third and final event of the session, Lamberti earned his first gold medal and set a Championships record and world record of 1:30.14 in the 4×50-metre medley relay with relay teammates Nicolò Martinenghi (breaststroke), Marco Orsi (butterfly), and Lorenzo Zazzeri (freestyle).

[14] The third day, Lamberti swam a personal best time of 50.86 seconds in the prelims heats of the 100 metre backstroke, ranked seventh overall, and did not advance to the semifinals as he was not one of the two fastest Italians in the event.

[19] Fourth day of competition, a similar situation arose, Lamberti swam a personal best time of 22.81 seconds in the 50-metre butterfly prelims heats, ranking behind Italians Matteo Rivolta and Thomas Ceccon and thus not advancing to the semifinals even though he ranked twelfth overall.

[29] Starting competition on day two, Lamberti ranked 14th in the prelims heats of the 100 metre butterfly with a time of 50.53 seconds and qualified for the semifinals of the event.

[31] The morning of day three, Lamberti advanced to the semifinals ranking tenth in the prelims heats of the 50 metre backstroke with a 23.50.

[33] Later in the day, Lamberti swam a 23.15 in the semifinals of the 50 metre backstroke to qualify for the final ranking sixth.

[43][44] On 24 June, he swam a time of 25.16 seconds in the preliminaries of the 50 metre backstroke, tying for sixteenth rank.

[57][58] The following day, he ranked sixth in the preliminaries of the 100 metre backstroke, qualifying for the semifinals with a time of 54.37 seconds.

[64] Starting off in the 50 metre backstroke on day one of the 2023 Italian National Spring Championships in April in Riccione, Lamberti took second-place behind Thomas Ceccon with a time of 24.95 seconds.

[69] Legend: sf – semifinal a split 22.62 (backstroke); with Nicolò Martinenghi (breaststroke), Marco Orsi (butterfly), Lorenzo Zazzeri (freestyle)