I have 40 databases on my vps which are devoted to storing databases. Previously the vps used 4 cpu cores and 16 gb ram but after vps i upgraded to 8 cores and 32 gb ram resulting in a spike in cpu usage by mysql. I'm using mysql 5.7 and using aaPanel 6.8.25 latest version. I have tried mysqltuner but couldn't solve it instead.

Here are my mysql settings
[client]
#password = your_password
port = 2345
socket = /tmp/mysql.sock

[mysqld]
skip_ssl
binlog_cache_size = 256K
thread_stack = 512K
join_buffer_size = 8192K
query_cache_type = 1
max_heap_table_size = 2048M
port = 2345
socket = /tmp/mysql.sock
datadir = /www/server/data
default_storage_engine = InnoDB
performance_schema_max_table_instances = 400
table_definition_cache = 400
skip-external-locking
key_buffer_size = 1024M
max_allowed_packet = 100G
table_open_cache = 2048
sort_buffer_size = 4096K
net_buffer_length = 4K
read_buffer_size = 4096K
read_rnd_buffer_size = 2048K
myisam_sort_buffer_size = 64M
thread_cache_size = 256
query_cache_size = 384M
tmp_table_size = 2048M
sql-mode=NO_ENGINE_SUBSTITUTION,STRICT_TRANS_TABLES

explicit_defaults_for_timestamp = true
skip-name-resolve
max_connections = 500
max_connect_errors = 100
open_files_limit = 65535

wait_timeout=25
interactive_timeout=25

log-bin=mysql-bin
binlog_format=mixed
server-id = 1
expire_logs_days = 10
slow_query_log=1
slow-query-log-file=/www/server/data/mysql-slow.log
long_query_time=3
#log_queries_not_using_indexes=on
early-plugin-load = ""

innodb_data_home_dir = /www/server/data
innodb_data_file_path = ibdata1:10M:autoextend
innodb_log_group_home_dir = /www/server/data
innodb_buffer_pool_size = 4096M
innodb_log_file_size = 512M
innodb_log_buffer_size = 128M
innodb_flush_log_at_trx_commit = 1
innodb_lock_wait_timeout = 50
innodb_max_dirty_pages_pct = 90
innodb_read_io_threads = 16
innodb_write_io_threads = 16
innodb_thread_concurrency = 0

[mysqldump]
quick
max_allowed_packet = 500M

[mysql]
no-auto-rehash

[myisamchk]
key_buffer_size = 256M
sort_buffer_size = 4M
read_buffer = 2M
write_buffer = 2M

[mysqlhotcopy]
interactive-timeout