Ignore the other 3 suits. The responder has found the suit to play. The responder does not know what the opener has in addition to 5+hearts, so should not be tempted by better looking suits. The opener may not be able to support its other suits. Act on what is known, not on what is hoped for.

By rebidding hearts, the responder is SUPPORTING the hearts. The opener knows the responder has at least 3-hearts and the partnership will play a hearts contract. The level of the responder's next bid indicates the point range of its hand, and will be used by the opener to find the appropriate contract level to play.

Support raises are not subject to the 1-over-1 restriction. If the responder has:
     6-9 pts:  Bid  2 ♥  - a single raise indicating the point count range. There are not enough combined partnership points for a game.
     10-12 pts:  Bid  3 ♥  - a double raise indicating the point count range. There are not quite enough combined partnership points for a game.
     13-16 pts:  Bid  4 ♥  - a triple raise to game. There are enough partnership points for a game in hearts. The opener will consider this bid as a close-out bid, and will likely pass.
     17-20 pts:  Bid  3 NT  - jump-shift raise indicates the responder's heart support and point count range. This commits the partnership to a game-level contract, and maybe more. This bid gives the opener the options to play the game level contract in No Trump, play the game level contract in 4-Hearts, or explore a slam contract.

The #1 priority is to support the opener's hearts. Support raises are not subject to the 1-over-1 restriction. If the responder has:
     6-9 pts:  responder has 2 options:
        • Bid  2 ♥  - a single raise indicating the point count range. There are not enough combined partnership points for a game.
        • Bid  4 ♥ *  - a special situation where there is a 5+card heart suit with a singleton Ace in another suit. The opener will consider this bid as a close-out bid, and will pass. The partnership with a 10+card heart fit and outside singleton Ace will likely succeed in making the game contract.
     10-12 pts:  responder has 2 options:
        • Bid  3 ♥  - a double raise indicating the point count range. There are not quite enough combined partnership points for a game.
        • Bid  4 ♥ *  - a special situation where there is a 5+card heart suit with a singleton Ace in another suit. The opener will consider this bid as a close-out bid, and will pass. The partnership with a 10+card heart fit and an outside singleton Ace will likely succeed in making the game contract.
     13-16 pts:  There are enough partnership points for a game in hearts. responder has 2 options:
        • Bid  4 ♥  with only a 3-card heart suit. This triple raise indicates both point count range and suit length. The opener will consider this bid as a close-out bid, and will pass.
        • Bid the  Jacoby 2 NT  - a special situation where there is opening count and a 4+card heart suit. This provides the opener the opportunity to explore a slam contract.
     17-20 pts:  There are enough partnership points for a game in hearts.
        • Bid  3 NT  - This jump-shift raise indicates the responder's point count range, and provides the opener the options to play the contract in No Trump, play the contract in 4-Hearts, or explore a slam contract.

The #2 priority is to propose the other major, the 4+card spade suit. Ignore the minor suits, and see if the opener also has a 4-card spade suit. An 8-card fit in spades may still be possible so the partnership can play a contract in a major suit.
Proposing a new 4+card spade suit at the 1-level is not restricted by the 1-over-1 restriction. When introducing a new suit, keep the bidding level as low as possible. If the responder has:

    • 6-16 pts:  Propose  1 ♠  - The 1-over-1 restriction allows bidding a new 4+card spade suit at the 1-level. This bid indicates no heart support, 6-16 points, and a 4+card spade suit. Since this bid is a new suit, the opener must respond.

    • 17-20 pts:  Propose  2 ♠  - This jump-shift indicates the responder's point count range and a 4+card spade suit at a low level. Since this bid is a new suit, the opener must respond.

When introducing a new suit, keep the bidding level as low as possible. If the responder has:

    • 6-9 pts:  Propose  1 NT  - The 1-over-1 restriction prohibits bidding a new suit at the 2-level. Instead of bidding PASS (which indicates 0 to 5 pts), the 1NT bid indicaties the point count range, no heart support, and no 4+card spade suit. However, there is a 4+card minor suit that cannot be mentioned. This keeps the bidding open for the opener.

    • 10-16 pts:  Propose the Better Minor suit  2 ♣  or  2 ♦  - This bid indicates 10-16 points, no heart support, and no 4+card spade suit. The mentioned minor suit will have at least 4-cards or more. Since this bid is a new suit, the opener must respond.

    • 17-20 pts:  Propose the Better Minor suit  3 ♣  or  3 ♦  - This jump-shift indicates the responder's point count range, no heart support, and no 4+card spade suit. The bid minor suit will have at least 4-cards or more. This bid provides the opener the options to play the contract in No Trump, play the contract in the proposed minor, or explore a slam contract. Since this bid is a new suit, the opener must respond.