Removing multiple delimiters between outside delimiters on each line

awk -F, '{ printf "%s,",$1;for (i=2;i<=NF-2;i++) { printf "%s ",$i };printf "%s,%s\n",$(NF-1),$NF }' file

Using awk, print the first comma delimited field and then loop through the rest of the field up to the last but 2 field printing the field followed by a space. Then for the last 2 fields print the last but one field, a comma and then the last field.

With GNU awk for the 3rd arg to match():

$ awk -v OFS=, '{
     match($0,/([^,]*),(.*),([^,]*)/,a)
     gsub(/,/," ",a[2])
     print a[1], a[2], a[3]
}' file
2020/11/04,Test Account,569.00
2020/11/05,Test Account,250.00
2020/11/05,More Test Accounts,225.00

or with any awk:

$ awk '
    BEGIN { FS=OFS="," }
    {
        n = split($0,a)
        gsub(/^[^,]*,|,[^,]*$/,"")
        gsub(/,/," ")
        print a[1], $0, a[n]
    }
' file
2020/11/04,Test Account,569.00
2020/11/05,Test Account,250.00
2020/11/05,More Test Accounts,225.00