His ability still isn't fully appreciated beyond Liverpool supporters because VVD is so brilliant.
If Joe Gomez isn't already one of the best centre-backs in the world, he's very close to that level. He's so far ahead of the other English centre-backs that it's a joke at this point - still only 23, a European Champion, a Premier League Champion, possesses every attribute you could want in a centre-back, learning from the very best in the world at his position and plays for the best manager in the game.
Just to emphasize this point, I've argued in favor of Gomez many a time against others and it's always the same 'he only looks so good because he's next to van Dijk'. Interestingly enough, because telling them to actually watch Gomez and see how amazing he already is doesn't really work, here are just some pure statistics:
As you can see above he's second in the league in loose ball recoveries (ahead of van Dijk) behind Kortney Hause. Liverpool have never lost a PL game in which Joe Gomez has started at CB. Since the beginning of the 2017/18 season their record with Joe Gomez at CB is 20 wins, 2 draws, with conceding 0.4 goals per game and having a 64% clean sheet rate; in the same time period without Joe Gomez at CB they've got 35 wins, 6 draws and 2 losses allowing 0.7 goals per game with a 39% clean sheet rate.
When Joe Gomez returned from injury this season this is how the team's performance changed (not updated to the end of the season, but I believe a 14 game sample):
Gheerbrant attributes a significant drop in shots faced (10.4 to 7.1) by Liverpool, shots on target faced (2.9 to 2.0) and expected goals value (1.01 to 0.70) of those chances to Gomez returning to the team, compared to the 14 games he didn’t feature in earlier this year.
Joe Gomez also as highlighted above has the highest recovery rate on the team ahead of van Dijk, he also plays the most passes per 90 mins on the team. His dribbling stats are also really impressive; much higher than van Dijk's or Matip's and also at a higher success rate. Joe Gomez also leads Liverpool in interceptions per 90 (along with the highest number of passes/crosses blocked per 90 of the centrebacks).
To me anyone deriding his class, or not recognizing the world class talent Joe Gomez already is needs to have their eyes checked or their glasses cleaned.