When I was in a similar situation, I told him that the things he was saying kind of lost their value through constant repetition and that it was more important to me to feel loved through his actions/how we were when we were together than to hear constant words.
I also pointed out (in the early days) that all the praise and 'lovey-ness' actually made me feel a bit uncomfortable, because he didn't know all my flaws yet and I felt like he had an idealised vision of me that I couldn't live up to.
Like someone else suggested, I said that I wanted to focus on one day at a time and how it felt to be together.
I am still with my DP four years later. He is much less prone to gushing these days 😁 (and I am a bit more vocal about how great he is).
I had previously been in a loveless marriage completely lacking in affection for a long time. I'm not particularly effusive myself either, so I just felt completely overwhelmed by the constant declarations of love and devotion. I didn't know how to accept them. It was a completely new experience for me.
My DP is a very positive, loving person. And he just wants to show his love. But I think even he would say now that he was feeling quite needy and a bit insecure at the time, and wanted to prompt me into saying the same things back to him. We also talked a bit about different ways of expressing love and trying to do that in ways we're both comfortable with.
Good luck, OP.