The centre-back departed Liverpool at the end of the 2023-24 season alongside Jurgen Klopp, Thiago Alcantara and Adrian following a glittering eight-year spell, having arrived on a free transfer from Schalke 04 in 2016.
Matip was tipped to return to the Premier League and was at one stage said to have received offers from three top-flight clubs, as West Ham United, Fulham and Bournemouth pursued a summer move for the Cameroonian.
However, Matip confirmed at the weekend that he had hung up his boots, and speaking to Sports Mole, Lynch labelled the 33-year-old a "phenomenal" defender in his best years, although he admitted that his fitness record was a minor blot on the notebook.
"An underrated player. Went under the radar like everyone who's Virgil van Dijk's partner tends to do, but he was phenomenal in his peak. The only criticism you would have of that transfer would be that he was a little bit injury prone," Lynch said.
"If he could have got on the pitch more frequently, I don't think there would have been any question marks about just how good a player he was because he was absolutely phenomenal in a key period for Liverpool, where they won everything."
Matip missed 140 Liverpool games through injury
"Just absolutely towering in the air and brilliant on the ball as well, so that's a pretty great combination to have as a central defender, and a much loved character in the dressing room as well."
During eight successful years at Liverpool, Matip became a Premier League and Champions League winner, in addition to achieving Club World Cup, FA Cup, EFL Cup, UEFA Super Cup and Community Shield glory at Anfield.
The ex-Cameroon international - who also became renowned for his brazen runs from the back - scored 11 goals and provided six assists in 201 matches for the Reds, but his Merseyside career was also blighted by numerous fitness problems.
Prior to joining Liverpool in 2016, Matip had only missed 17 games for club and country, but he sat out a staggering 140 matches for Klopp's side, including 37 in his final season due to a cruciate ligament tear.
The centre-back played just 14 times for Liverpool in 2023-24 and was denied a proper on-field farewell due to his ACL injury, and he was also absent for the second half of the 2020-21 season on account of an ankle issue.
'Speaking to cheeky Matip was like pulling teeth'
In spite of his terrible luck with injuries, Matip remains a fan favourite on Merseyside, and Lynch believed that his "cheekiness" played a huge role in that, even if it was difficult to pry information out of him.
"Kind of a quiet character - I interviewed him and it was a bit like pulling teeth at times, to be honest. Couldn't really get loads out of him, but he was a really nice guy, very polite," Lynch added.
"Sort of a quiet guy, but showed a little bit more of his cheekiness in a dressing room setting, and he was absolutely loved at Liverpool and a brilliant player as well. So a shame that his body's letting down and he can't play for a little bit longer, but I hope he enjoys his retirement because he was always great to deal with."
Liverpool did not sign a direct replacement for Matip in the summer transfer window, but they recently tied Jarell Quansah down to a new long-term contract, and Ibrahima Konate is also expected to extend his Reds deal in the near future.
However, Van Dijk could still leave for nothing when his current contract runs out at the end of the season, and uncertainty also lingers over the future of Joe Gomez, who was heavily linked with an exit in the summer.