In the attacks I've seen, the incrementing of a value suggests a couple of scary possibilities:
a) The attacker successfully found some SQL injection vulnerability and is incrementing some value to exfiltrate a data table, one record at a time.
b) The attacker is attempting a buffer overflow exploit, and is trying to determine the right memory offset.
Your posted query string examples look to me more like situation a. Situation b tends to increase the character length of the requested string.
On the other hand, these attacks seem quite commonplace, so he presence of this incrementing behavior doesn't definitively mean there is any exploit in progress. Here are some entries from my apache log recently:
170.106.99.215 - - [26/Aug/2021:11:54:59 +0000] "GET /community/home.php?p=1+%27-6863+union+all+select+1,1,CONCAT(0x3a6f79753a,0x4244764877697569706b,0x3a70687a3a)1,1,1%23 HTTP/1.0" 301 672 "-" "-"
170.106.99.215 - - [26/Aug/2021:11:54:59 +0000] "GET /community/home.php?p=1+-6863+union+all+select+1,1,CONCAT(0x3a6f79753a,0x4244764877697569706b,0x3a70687a3a)1,1,1,1%23 HTTP/1.0" 301 670 "-" "-"
170.106.99.215 - - [26/Aug/2021:11:55:00 +0000] "GET /community/home.php?p=1+-6863+union+all+select+1,1,CONCAT(0x3a6f79753a,0x4244764877697569706b,0x3a70687a3a)1,1,1,1,1%23 HTTP/1.0" 301 674 "-" "-"
You might consider requesting one of these urls to see how your site responds.