There is no need to reinstall.
systemctl disable spamd
systemctl stop spamd
systemctl disable clamav-daemon
systemctl stop clamav-daemon
v-change-sys-config-value ANTIVIRUS_SYSTEM ''
v-change-sys-config-value ANTISPAM_SYSTEM ''
Edit exim4 conf /etc/exim4/exim4.conf.template and comment these lines:
Before:
SPAMASSASSIN = yes
SPAM_SCORE = 50
SPAM_REJECT_SCORE = 100
CLAMD = yes
After:
#SPAMASSASSIN = yes
#SPAM_SCORE = 50
#SPAM_REJECT_SCORE = 100
#CLAMD = yes
Save the file and restart exim.
systemctl restart exim4