First off, nobody is saying we will never experience opposition. We are told in 1 Peter 5:8 to be sober, be vigilant; because your adversary the devil, as a roaring lion, walks about, seeking whom he may devour... "may" as in who is going to allow him to attack with success.
We are told in Mark 4:13-20 that the devil seeks to take God's Word away and choke God's Word out of our lives so God's Word is not fruitful or becomes ineffective.
Health is not automatic... once the enemy gets people to accept it, they bare fruit unto being sick because they accept it as being something they cannot do anything about. That's not true because all things are possible with God... but we are going to have to walk by faith (in what God promised) and not by sight (2 Corinthians 5:7) meaning there is most likely going to be some time when you are believing God's promises without any physical evidence that God's promises are true for you.
I've experienced that in other areas of my life, but thankfully the way health was presented to me years ago was that is was a done deal, Jesus had taken my sickness / disease upon Himself so that I would not have to have it and I do not have to have it... even if it tries to come on me.
God's promises are God's Word, God's Word is His will, otherwise He would not have promised it... God's Word changes things because God's power in in His Word. If anybody has a problem with that need to take that up with God and ask the Lord to forgive them for thinking God's Word is not true.... repent for calling God a liar!
The following scriptures specifically speak to physical healing... either you believe what God said and you make up your mind His Word is true and you start seeking His wisdom concerning how to get there from here, or you don't:
James 5:14,15
Is any sick among you? let him call for the elders of the church; and let them pray over him, anointing him with oil in the name of the Lord:
And the prayer of faith shall save the sick, and the Lord shall raise him up; and if he have committed sins, they shall be forgiven him.
Note: If you have no elders in your church that can pray the "prayer of faith" you might call around to some other churches in the area.
Proverbs 4:20-23
Attend to My words; incline your ear unto My sayings....let them not depart from your eyes; keep them in the midst of your heart....for they are life unto those that find them, and health to all their flesh....keep your heart with all diligence; for out of it flow the forces of life.
Matthew 8:17
That it might be fulfilled which was spoken by Esaias the prophet, saying, Himself took our infirmities, and bare our sicknesses.
Isaiah 53:4, 5
Jesus has carried our grief (pain, anxiety, calamity, disease, sickness), and carried our sorrows (anguish, affliction, feelings of pain, sadness and sorrow): yet we did esteem Him stricken, smitten of God, and afflicted....but He was wounded (to wound, to break, be slain or killed) for our transgressions, He was bruised (crush, destroy, oppress, to collapse) for our iniquities: the punishment (violence, rebuke) of our peace was upon Him; and with His stripes we are healed. (He took our wounds, so we could take his wholeness & health in every area of life)
NOTE: Go look up the word "grief" in the Hebrew and see that is includes sickness / disease.
The devil will send many your way to tell you this is all false which is what the devil always does... opposes God's promises. When he does this, it's a sign that he is worried that you will in fact accept God's promises and become well at some point in the not too distant future.
Here's a couple more to consider concerning learning WHAT to do...
James 1:5-8
If any of you lack wisdom, let him ask of God, that giveth to all men liberally, and upbraideth not; and it shall be given him.
But let him ask in faith, nothing wavering. For he that wavereth is like a wave of the sea driven with the wind and tossed.
For let not that man think that he shall receive any thing of the Lord.
A double minded man is unstable in all his ways.
And, God is not putting sickness or disease on anyone to teach them... He uses His Word and the Holy Spirit to teach
James 1:13
Let no man say when he is tempted, I am tempted of God: for God cannot be tempted with evil, neither tempts he any man:
Tempts = testings, temptations, trials... God is not the One bring these things on people and it's satan running PSYOP (psychological operations, or psychological warfare) to spread false information to try and get people to believe God is putting it on them because people will lay down their resistance if they think it's God putting it on them for some reason.
At any rate, I will agree and believe with you that your health returns quickly and that you become able to walk free is sickness which does include utilizing common sense things such as eating right, getting plenty of exercise, taking some good daily vitamins to help your body get plenty of nourishment (you'd have to eat a bunch of different types of food to get this), staying out of strife and stress, getting plenty of sleep.... and otherwise take care of your body which is the Temple of the Holy Ghost (1 Corinthians 6:15-20)