How to "make" a variable that contains another variable value?

Question

I'm back to (very modest) scripting after 20+ years outside of that domain.

I'd like to write a small script that pings some IP addresses (some internal and wired, some internal over CPL, some external) to troubleshoot the instability of my network connectivity.

I do a single ping to each host, and if it's down, it adds a line to a file named host_.txt

I don't need alerting, just logging.

I've read many posts here, and my current script was leaning towards the below.

As you can see, I'm storing 2 (stupid and fake for now) IPs in variables $IP1 and $IP2. I don't want to duplicate the code for each ping, so I basically wanted to encapsulate it in a "for" loop and use the value of the "i" counter to point to the correct variable ( IP$i would then give me IP1, IP2, ...).

My problems/questions:

1. If I concatenate "IP" with $i, I end up with the name of my variable: IP1, IP2, ... but how can I refer to the value of this variable?
2. More in general, is this "while true" a good method to have the script running continuously, as "ping" would do without its "-c" parameter? Won't it use too much resources on my small Raspberry Pi?
3. Would it be better to consider building a list or a table of IPs, and go through that list without requiring the storage of IPs into separate variables?

Any other recommendations are most welcome!

Many thanks

#!/bin/bash                                                                                                              IP1=127.0.0.1 IP2=127.0.0.2 while true do
    stamp=$(date +"%Y%m%d-%T")
    for i in $(seq 1 2)
    do
        target=IP$i
        ping -c1 -W10 $target
        if [ $? -ne 0 ]; then echo $target "KO at" $stamp > host_$IP$i.txt ; else echo $IP$i "OK > at" $stamp ; fi
    done
    sleep 1 done

For info, I also tried this, without success..

#!/bin/bash                                                                                                             
IP1="127.0.0.1"
i=1
echo IP$i
echo $(echo "IP";echo $i)

EDIT: For the sake of documentation, with focus on the initial issue: "If I concatenate "IP" with $i, I end up with the name of my variable: IP1, IP2, ... but how can I refer to the value of this variable?"

This technique is called "indirect" and is documented in stackoverflow.com/tags/bash/info

My solution was simply to do this:

for i in $(seq 1 2)
do
target="IP"$i
echo "${!target}"
#I can then do smth like ping -c1 -W10 ${!target}
done

Hope this helps others!