T.A.M.:
If there were any other way to obtain forgiveness of sins, become acceptable (pure) to be able to exists in God's presence (get into Heaven), then Christ didn't have to die, right? The fact that it was necessary for Him to die means that our salvation cost God a VERY high price!
Being 'good' and kind and moral and compassionate, etc. is fine BUT IT WILL NOT PURIFY US! ONLY Christ's shed blood can purify us - and we have to accept His sacrifice willingly and humbly. Those are God's rules, not ours. The rules we make up are useless. God can 'change your mind' about this
PS I am a 66-year old father of 4 adult children and retired Information Technology executive - so I am a lot older than you

I have a very close friend who is a retired university president and professor - he is an ecumenist, which sounds like you. I keep telling him that being a moral, kind, loving person to all those around him (which he is) will not be sufficient. We don't know what is in store for those who never knew (about) Christ. But He told the world what is in store for those who reject His sacrifice. If there were ANY other way, God would have thought of it!
It's not so much a matter of being a 'believer' in a certain religion but being a 'follower (disciple) of Christ'. Many so-called 'Christians' are not really followers of Christ!