Mysql Windows Performance Problem My system:

2X E5 2680 V3 Cpu
32 GB Ram
Windows 7 Pro


Apache 2.4.41
Mysql 8.0.17

I have a script and this for Customer Online Chat Script.  I have 10 clients for customer support.  It uses php json and ajax.  It generates high select query.
What can I do?  Is there any my.cnf example for this usage?
[client]
no-beep

# pipe
# socket=0.0
port=3306

[mysql]

default-character-set = UTF8MB4

[mysqld]
port=3306
basedir="C:\AppServ/MySQL"
datadir="C:\AppServ/MySQL/data/"
character-set-server = UTF8MB4

sql-mode=""
log-output=FILE
general-log=0
general_log_file="mysql.log"
slow-query-log=1
slow_query_log_file="mysql-slow.log"
long_query_time=3
log-error="mysql-error.log"
server-id=1


secure-file-priv="datadir="C:\AppServ/MySQL/Uploads"

max_connections=500

table_open_cache=4000

tmp_table_size=1024M
max_heap_table_size=1024M

thread_cache_size=200
myisam_max_sort_file_size=100G
myisam_sort_buffer_size=975M
key_buffer_size=512M

read_buffer_size=256K
read_rnd_buffer_size=256K


innodb_flush_log_at_trx_commit=1


innodb_log_buffer_size=1M


innodb_buffer_pool_size=20000M


innodb_log_file_size=250M


innodb_thread_concurrency=0


innodb_autoextend_increment=6
innodb_buffer_pool_instances=16


innodb_concurrency_tickets=5000


innodb_old_blocks_time=1000


innodb_open_files=600


innodb_stats_on_metadata=0


innodb_file_per_table=1


innodb_checksum_algorithm=0

back_log=80


flush_time=0


join_buffer_size=256K


max_allowed_packet=4M


max_connect_errors=100


open_files_limit=5161


sort_buffer_size=256K


table_definition_cache=1400


binlog_row_event_max_size=8K


sync_master_info=10000


sync_relay_log=10000

sync_relay_log_info=10000

default_authentication_plugin=mysql_native_password
I will be crazy. Only 20k line data and 10 online client how can be slow like fax :S
My system uses SSD disk.
SHOW GLOBAL STATUS pastebin.com/gLvTkZ6s
SHOW GLOBAL VARIABLES pastebin.com/UcJkxRKb
SHOW FULL PROCESSLIST pastebin.com/AaWGFurJ
SHOW ENGINE INNODB STATUS pastebin.com/aQYLW1FH
SELECT name, count FROM information_schema.innodb_metrics ORDER BY name pastebin.com/Wdz1WhU6My
My system generates query like : SELECT count(id) FROM gr_msgs WHERE gid = '1-573' AND id &gt; '5989' gr_msgs